I know a guy working on a related idea. Instead of funding people, his system works by funding issues. The link is http://www.freedomsponsors.org

The workflow, as I understand it, goes something like that:

1) There's an issue on a project you use that's getting no love.

2) You go to freedomsponsors register that you'd like some issue solved, so much that you'd be willing to put your money where your mouth is. Also, you'll probably want to put a link to freedomsponsors on the project's issue tracker.

3) When one or more people solve the issue, the sponsor pays them (if more than one person has worked on the issue, the sponsor can distribute the money in anyways).