Where can I find a reference for someone becoming a sotapanna through meditation?

There were a few who reached Sotapanna and higher stages through Anapana and Vipassana meditation only. Webu Sayadaw, Sayagyi U Ba Khin, Sayamagyi, and a teacher in Goenkaji tradition. A few teachers before that were Ledi Sayadaw and Saya Thetgyi.

It's not possible to find an evidence where there is no evidence.

Althought there is bbroad believe that Path can be gained by (simply) meditation, it's not the case.

Why? Because the path has right view as it's base, right view as it's foundation. And as taught:

"In a person of wrong view, wrong resolve comes into being. In a person of wrong resolve, wrong speech. In a person of wrong speech, wrong action. In a person of wrong action, wrong livelihood. In a person of wrong livelihood, wrong effort. In a person of wrong effort, wrong mindfulness. In a person of wrong mindfulness, wrong concentration. In a person of wrong concentration, wrong knowledge. In a person of wrong knowledge, wrong release.

"This is how from wrongness comes failure, not success."

— AN 10.103

And how is right view gained? By the Voice

"Monks, there are these two conditions for the arising of wrong view. Which two? The voice of another[1] and inappropriate attention. These are the two conditions for the arising of wrong view."

"Monks, there are these two conditions for the arising of right view. Which two? The voice of another and appropriate attention. These are the two conditions for the arising of right view."

And as quoted by others, ther are outwardly conditions which are conductive to meet such.

Just for example, if one learns to recite, including understanding the meaning, once proper attention might be there and one remembers (e.g. hears the voice) than right view can be gained, the path developed and realized.

So one does not act wise to seek after meditators but primarily after people having, teaching, training right view. That should ones effort to gain the stream:

"One tries to abandon wrong view & to enter into right view: This is one's right effort...

"One tries to abandon wrong resolve & to enter into right resolve: This is one's right effort...

"One tries to abandon wrong speech & to enter into right speech: This is one's right effort...

"One tries to abandon wrong action & to enter into right action: This is one's right effort...

"One tries to abandon wrong livelihood & to enter into right livelihood: This is one's right effort."

— MN 117

One can meditate for eons not even near and still an outsider:

Nandiya Sutta: To Nandiya

On one occasion the Blessed One was staying among the Sakyans near Kapilavatthu in Nigrodha's Park. Then Nandiya the Sakyan went to the Blessed One and, on arrival, having bowed down to him, sat to one side. As he was sitting there he said to the Blessed One, "Lord, the disciple of the noble ones in whom the factors of stream entry are altogether & in every way lacking: Is he called a disciple of the noble ones who lives heedlessly?"

"Nandiya, the person in whom the factors of stream entry are altogether & in every way lacking I call an outsider, one who stands in the faction of the run-of-the-mill. But as to how a disciple of the noble ones lives heedlessly and heedfully, listen well and pay attention, I will speak"...

For more about how to gain the stream (and no wise would suggest: go meditate!) see: Into the Stream

Do! Don't be heedless, since

Sole dominion over the earth, going to heaven, lordship over all worlds: the fruit of stream-entry excels them. — Dhp 178

And what would one have gained in wasting time with meditation if not based on firm right view?

All an act of will? Or natural by having given causes?

[Note: This is a gift of Dhamma, not meant for commercial use or other lower wordily gains by ways of exchange or trade]

IE Anapanasati Sutta

"In this community of monks there are monks who remain devoted to the development of the four frames of reference... the four right exertions... the four bases of power... the five faculties... the five strengths... the seven factors for awakening... the noble eightfold path: such are the monks in this community of monks.

"In this community of monks there are monks who remain devoted to the development of good will... compassion... appreciation... equanimity... [the perception of the] foulness [of the body]... the perception of inconstancy: such are the monks in this community of monks.

"In this community of monks there are monks who remain devoted to mindfulness of in-&-out breathing.

"Mindfulness of in-&-out breathing, when developed & pursued, is of great fruit, of great benefit. Mindfulness of in-&-out breathing, when developed & pursued, brings the four frames of reference to their culmination. The four frames of reference, when developed & pursued, bring the seven factors for awakening to their culmination. The seven factors for awakening, when developed & pursued, bring clear knowing & release to their culmination.

Satipatthana Sutta:

"This is the only way, monks, for the purification of beings, for the overcoming of sorrow and lamentation, for the destruction of suffering and grief, for reaching the right path, for the attainment of Nibbana, namely, the four foundations of mindfulness."

Liberation Sutta:

(5) “Again, neither the Teacher nor a fellow monk in the position of a teacher teaches the Dhamma to a bhikkhu, nor does he teach the Dhamma to others in detail as he has heard it and learned it, nor does he recite the Dhamma in detail as he has heard it and learned it, nor does he ponder, examine, and mentally inspect the Dhamma as he has heard it and learned it, but he has grasped well a certain object of concentration, attended to it well, sustained it well, and penetrated it well with wisdom. In whatever way the bhikkhu has grasped well a certain object of concentration, attended to it well, sustained it well, and penetrated it well with wisdom, in just that way, in relation to that Dhamma, he experiences inspiration in the meaning and inspiration in the Dhamma. As he does so, joy arises in him. When he is joyful, rapture arises. For one with a rapturous mind, the body becomes tranquil. One tranquil in body feels pleasure. For one feeling pleasure, the mind becomes concentrated. This is the fifth basis of liberation, by means of which, if a bhikkhu dwells heedful, ardent, and resolute, [24] his unliberated mind is liberated, his undestroyed taints are utterly destroyed, and he reaches the as-yet-unreached unsurpassed security from bondage.“These, bhikkhus, are the five bases of liberation, by means of which, if a bhikkhu dwells heedful, ardent, and resolute, his unliberated mind is liberated, his undestroyed taints are utterly destroyed, and he reaches the as-yet-unreached unsurpassed security from bondage.”

Here the term Bhikkhu is used not Ariya Savaka as one would expect if it was dealing with Sotapannas, some people claim that the early Suttas the term Ariya Savaka was used loosely even. So the fact that it is not used here is strong evidence that it means what it seems to mean.

i dont think there are passages that i know of in the Sutta Pitaka that state it explicitly how OP asks because in the Sutta the term Sotapanna is used rather loosely, evidently from "Faith Follower", "Dhamma Follower" definitions ie. This is also evident from Ratana Sutta etc where The Noble Individuals constitute Four Pairs, so a pair of Sotapanna at least. Abhidhamma talks about one Cula-Sotapanna.

So what is evident however one looks is that there are several people who according to Suttas can be referred to as Sotapanna of some sort. There are those incapable of passing away before realizing the fruit, do not have the Path but have Right View;

one who has entered the fixed course of rightness, entered the plane of superior persons, transcended the plane of the worldlings.

So there it is very safe to say based on the Sutta Pitaka alone that there are Noble People who have not realized Nibbana and the Three Fetters but have Right View, wereas the other becomes fixed in Right View.

Dhammapada Verse178 (Anathapindikaputtakala Vatthu) says: “Higher than being a Monarch, greater than being born in the Deva Lokas, or heavenly planes, greater than being a ruler of the three worlds, higher than all of these is the attainment of Sovan (Sotapanna / The Way to Stream Entry)
At this stage the practitioner / sothapanna, begins to understand that there is the deed but not the doer, and this knowing is complete in an Arahant. We have to understand that there is no individual who owns body, feeling, perception, thought and consciousness. That is the most difficult aspect of the Buddha’s teaching. Difficult to conceptualize and even more difficult to experience. Without meditation, it will remain an intellectual exercise. For this one’s meditation should be exactly as per Supreme Buddha’s instructions found in the many suttas like Girimananda Sutta, Ananda Sutta etc.

To understand a simpler person, who is a sotapanna, it is good to read the story of Kukkuta Mltta the hunter and his family comprehend the Dhamma. The story is about a girl who had comprehended the Dhamma, marrying a hunter. In explaining the actions of this hunters wife, Buddha said:

'Bhikkhus, those who are sotapannas don't kill, they don't wish others to get killed. The wife of the hunter was only obeying her husband in getting things for him. It never occurred to her to think she was helping her husband to commit evil deeds. Just as the hand that has no wound is not affected by poison, so since she has no intention to commit evil she has not created any bad kamma.'

The first of the three fetters which the Sotāpanna eradicates is strong self Identity view (Strong ego) / Sakkaya Dhitti - The view that there is a permanent controllable self or soul which can be considered ME/MINE/MY SOUL / MY SELF, which survives after the death. In other words it is the speculative view that a so-called self / Soul (Atta/ Atman exists in the five aggregates of clinging (physical forms, feelings/sensations, perception, mental formations and consciousness), is eradicated because the Sotāpanna gains insight into the selfless nature of the aggregates.

Sakkaya Dhitti is explained in detail in.. Chula vedalla Sutta: The Shorter Set of Questions-and-Answers.

Skeptical Doubt is the second of the three fetters which the Sotāpanna eradicates. - Doubt about Supreme Buddha and his teaching is eradicated by a Sotapanna, because the Sotapanna personally experiences the true nature of reality through insight, and this insight confirms the accuracy of Buddha’s teaching. There is no need for a Sotapanna to associate teachers to take advice to develop spiritually. Through intuition he knows what to do.

Clinging to rites, rituals and superstitions is the third of the three fetters which the Sotāpanna eradicates. - Clinging to the view that one becomes pure simply through performing ritual or rigid moralism, such as relying in a god for non-causal deliverance, slaughtering animals for sacrifice, ablutions, following superstiotions, Astralogical auspicious ways..etc. is eradicated because the Sotāpanna realizes that the excessive rites, rituals and superstitions are nothing more than an obstructive tradition and deliverance can be won only through the practice of the Noble Eightfold Path.

The fifty-fifth Samyutta of the Samyutta Nikaya is called the Sotāpatti-saṃyutta, and concerns Sotapannas and their attainment. In Sutta-numbers of chapter 1-4, 6-9, 11-14, 16-20, 22-36, 39-49, 51, 53, 54, Sotapannas are praised as a part of the Ariya Sangha.

The Anguttara Nikaya (A.iv,392-95) records a fabulous alms-giving conducted by the Bodhisatta when he was born as a brahman named Velama. Lavish gifts of silver, gold, elephants, cows, carriages, etc., not to mention food, drink and clothing, were distributed among everybody who came forward to receive them. But this open-handed munificence was not very valuable as far as merit was concerned because there were no worthy recipients. It is said to be more meritorious to feed one person with right view, a stream-enterer (sotapanna), than to give great alms such as that given by Velama. It is more meritorious to feed one once-returner than a hundred stream-enterers. Next in order come non-returners, arahants, Paccekabuddhas and Sammasambuddhas.

@dmsp.. your question was how to become a Soptapanna (Stream Entrant) through meditation. So I will give a short answer as I do not want the answer to be too lengthy. The meditative way to go about it is this:

Here one should be aware that there are two levels in this Noble Eightfold Path. It is the laukika and the lokottrara levels. Almost all of us that identify ourselves as ‘Buddhists’ are at the ‘laukika’ level. It is the "mundane" (or "worldly") level where we try to follow the Noble Eightfold Path with expectations of a better life now and in future lives, depending on our beliefs, or need, or level of knowledge. As a result we also gain ‘kleshas’ & ‘upakkleshas’ at this mundane level. Buit it is not so at the lokottrara level. This is the "supramundane"(or "transmundane") level where no ‘kleshas’ & ‘upakkleshas’ develop.

If we want to work towards this higher level we have to be like the “kata kirilli”. The Buddha had referred to the kata kirilli, the common hedgebird, found in paddy fields, in the Sakunagghi Sutta-The Hawk. The kata kirilla builds its nest under the mud raised by ploughing the fields, and as long as it stays there, that’s it’s safeguard. Likewise our safeguard is the Satara Satipatthāna (The four foundations of mindfulness).

The path to free oneself from suffering is the Satara Satipatthāna (The four foundations of mindfulness), which means establishing one’s mind (on it). One should learn it with utmost respect and establish one’s mind according to it, if one wants to embark on this road less travelled. Then we will be able to free our minds from other external ‘mundane’ objectives and concentrate on the Satara Satipatthāna (The four foundations of mindfulness). If one could do it, then it is the Sapta Bojjañga (the Seven Factors of Enlightenment) that is going to get developed in him/her. That is, the items that aid in attaining realization of the Path, that will start to get developed. There are seven items that aid realization. They are: Sati (mindfulness); Dhammavicaya (investigating the Dhamma); Viriya (effort; energy); Pīti (happiness); Passaddi (tranquility); Samādhi (concentration) and pēkkā (equanimity).

We will start to understand that cultivation little by little (Sati). When a mind concentrate on the Dhamma in this manner, one will develop the talent of investigating the Dhamma by his wisdom (Dhammavicaya). When the talent of investigating Dhamma by his mind is developed, his effort gets cultivated (Viriya). When effort is developed, happiness gets cultivated (Pīti). When happiness is formed, alleviation/tranquility with respect to his (physical) body and mind gets cultivated (Passaddi). When he feels that relaxation with respect to his body and mind, his mind gets concentrated (Samādhi). A concentrated mind will become temperate since it is cultivated by wisdom (Upēkkā). This mind we have can be cultivated to that level.

Through meditation, the seven factors are developed sequentially since mindfulness factor leads to investigative analysis and so on. Anapanasati sutta (Majjima Nikaya) explains development of the seven factors:

"How bhikkus do the four foundations of mindfulness developed and cultivated, fulfill the seven enlightenment factors? Bhikkhus, on whatever, occasion a bhikkhu abides contemplating the body as body, ardent, fully aware, and mindful, having put away covetousness and grief for the world – on that occasion unremitting mindfulness is established in him. On whatever occasion unremitting mindfulness is established in a bhuikkhu - on that occasion the mindfulness enlightenment factor is aroused in him, and he develops it and by development it becomes to fulfillment in him. Abiding thus mindful he investigates and examines the state with wisdom and embarks upon a full inquiry into it. "

As stated in SN 13.1, sotappana (stream-entry) requires acquiring/having the Dhamma-Eye (dhamma-cakkhu-paṭilābho).

In his 1st sermon (SN 56.11), the Buddha said the noble eightfold path (the middle way) gives rise to insight or the dhamma eye (cakkhu-karaṇī). Therefore, eight factors, including three meditation factors, are required for stream-entry, which is why SN 55.5 states the streamwinner is one who is endowed with this noble eightfold path itself.

After the 1st sermon was given, the stainless dhamma-eye arose only in Koṇḍañña of “whatever is subject to origination is all subject to cessation.”(koṇḍaññassa virajaṃ vītamalaṃ dhamma cakkhuṃ udapādi: “yaṃ kiñci samuda­ya­dhammaṃsamudaya sabbaṃ taṃ nirodhadhamman”ti).

For Koṇḍañña to have this insight, particularly the insight of cessation (of craving, self-becoming & suffering), his mind must have been free from the five hindrances, otherwise he could not have experienced cessation (nirodha) & tasted Nibbana. Whenever, the mind is free from the five hindrances, it will naturally have samadhi. Here, AN 5.51 states:

And when a monk has not abandoned these five obstacles, hindrances that overwhelm awareness and weaken discernment, when he is without strength and weak in discernment: for him to understand what is for his own benefit, to understand what is for the benefit of others, to understand what is for the benefit of both, to realize a superior human state, a truly noble distinction in knowledge & vision: that is impossible.

It follows to attain stream-entry requires having some degree of noble concentration (but not necessarily jhana; 'neighbourhood concentration' is sufficient) or 'meditation'. MN 117 defines noble concentration as:

...noble right concentration with its supports and its requisites, that is, right view, right intention, right speech, right action, right livelihood, right effort, and right mindfulness...

MN 56 describes the stream-entry of the householder Upali. MN 56 clearly states Upali's mind was free from the five hindrances (nīvara­ṇa­), i.e., had samadhi/meditation, prior to the stream-entry:

Then the Blessed One discoursed to him a graduated sermon, that is to say, he spoke on the subjects of liberality, virtue, the heavens, on the evil consequences, the vanity and the depravity of sensual pleasures and on the advantages of renunciation.

When the Blessed One perceived that the mind of Upāli, the householder, was prepared, pliant, free from hindrances (vi-nīvara­ṇa­-cittaṃ), elevated and lucid, then he revealed to him that exalted doctrine of the Buddhas, viz. Suffering, its Cause, its Ceasing and the Path.

Just as a clean cloth, free from stain, would take the dye perfectly, even so, to Upāli, the householder, whilst seated in that place, there arose (in him) the spotless, stainless vision of Truth. He knew: Whatsoever has causally arisen must inevitably pass utterly away.’

Then Upāli, the householder, having thus, in the Dispensation of the Exalted One seen the Truth; attained to the Truth; comprehended the Truth, penetrated the Truth, overcome doubt; cast off uncertainty and gained full confidence without dependence on another.

In conclusion, intellectual or 'book' knowledge of Buddhism alone, even if it is Right View, cannot result in stream-entry because, as described in every example above, the mind of the stream-enterer must be free from the five hindrances and, more importantly, must have the experience of nirodha (cessation) and taste Nibbana.

For stream-entry to occur, as described in MN 117, Right View plus the meditation factors of Right Effort & Right Mindfulness must function together in unison:

One makes an effort for the abandoning of wrong view & for entering into right view: This is one's right effort. One is mindful to abandon wrong view & to enter & remain in right view: This is one's right mindfulness. Thus these three qualities — right view, right effort & right mindfulness — run & circle around right view. MN 117