That's interesting, I've always wanted to do something like that and never really figured out how. Mind giving details? Or if you'd rather not do it here, just send me an email, it's my username at gmail.
The people running the coop are responsible for finding us the new contracts, and they add something on top while I get to charge decent rates. I know I could probably market myself and earn the same thing without the middleman, but I don't have to worry about keeping the pipeline full, billing, negotiations, etc.. having someone else handle that frees me up to focus on development.
The nice thing about this arrangement is that since we're a team we can work on larger projects than I would otherwise be able to bid on myself. Instead of having to juggle 5 or 10 projects to fill all my billable hours in a month, I can easily do it with just a couple. I'm also able to go much deeper and work on 6-12 month contracts, rather than doing short, trivial projects.