[KyleGalvin]

The extreme of the bottom end is couchsurfing.com which might chew into the niche you describe.

There is still some room in the middle, but success isn't guaranteed in that sort of market.

[akhunt1002]

I think transaction is important because it's explicit, and people are far likelier to respond. Couchsurfing is free, so the incentive is low, but the community is the most important part of it. I think combining community and transaction is a huge opportunity (I'm also biased :))