score:5
Renting in Scandinavia is quite expensive: I found quotes for 5000 SEK for a week for a touring MC (that's dirty cheap and not representative), plus extra for accessories (2000 SEK for complete set of helm, bags etc.), plus 1 SEK/km, plus cost of accommodation (500 SEK/person on average for a reasonable accommodation, in Norway even more expensive), plus cost of sustenance (400-500 SEK/day if going out to eat, 100 SEK/day or less if you'll be preparing food yourself).
For a two-week 2000 km trip, that makes ~30000 SEK ~(3300 EUR) minimum per person without the cost of fuel (14.5 SEK-15 SEK per liter of petrol approximately).
There might be minimum age restrictions (drivers under 24-26 are insured for higher premiums in Sweden, and might not be allowed to rent an MC). Concerning going to Norway -- shouldn't be a problem generally if you inform the renting agency. Might increase insurance premium though.
As to how to find them: "hyr motorcykel" in your favourite search engine should do the trick. Many sites won't have English versions, so be prepared for some translation. Renting agencies won't have problems speaking to you in English on the phone though. At this price level, I'd recommend contacting some directly, explain your plan and see if you can get a better deal from them.