I've seen Kickstarter used for open source apps fairly successfully before. (Sorry I don't remember one off the top of my head.) I don't see any reason to reinvent the wheel here. Maybe even contact Kickstarter and ask if they can build a section for it?

The compensation I get for developing open source projects is recognition in the community, a nice resume padder and a general feel good associated with donating because I generally don't just donate straight up money to anything.

When I can walk into a possible employer and hand them a long list of projects I've worked on then they can see exactly my capabilities. I get job offers much easier without having to jump through hoops to prove coding skills directly.