So how is this different from Flattr (http://flattr.com/), apart from recurring instead of one-time payments?
The update is that I hung out with Flattr's bizdev, @gaiapunk, at #xoxofest, and we had a great time. I love the spirit and vision behind Flattr. IMO their hands are tied because they're a traditional pound-of-flesh business. Gittip is funded on Gittip.
For open source projects, maybe one solution could be to have a flattr button on each git push, or each small release..