Upvote:2
You should NOT have a problem entering. Should you somehow be flagged for suspicion of illegally working, you have the 20k THB + flight ticket out + rental contract (show only what they ask). There is nothing official that would prevent you from coming and being allowed to enter. Unofficially, some immigration offices seem to be tracking extensions and maybe counting them as entries. But again, your case should have no issues. In the event that a particular airport is being difficult, consider a land entry or an alternate airport.
The problem with this question is that, while the OP does a great job of describing his travel history, different borders can have slightly different policies on what is acceptable. For example, some Malay borders (like Sadao/Dannok) require an overnight stay (no same-day "out-in" bouncing). The majority of the people should have no issues as there are many people who travel yearly to Thailand and do their winter months, 1/2 year thing, etc entirely on METV or SETV + [SETV/VE/Extension].
If you really want to stay in Thailand full time (greater than 8 months/270 days per year), consider METV, Elite Visa, or non-imm visa. Your first year bouncing around isn't such a big deal. Eventually it would get old, especially if you live very far from the more convenient land/air borders.
edit: See a somewhat related post on Visa Exempt entry limitation.