I had a similar idea: Musicians upload bits of music (could be a riff, drum track, solo, vocal, whatever) and collaborate on combining them, altering parts as n

I had a similar idea: Musicians upload bits of music (could be a riff, drum track, solo, vocal, whatever) and collaborate on combining them, altering parts as necessary, etc. You can then mix the bits together into a final track, get feedback on your parts, and so on. To make money you could sell the final track on iTunes or press CDs (t-shirts?) and the site will track which musician gets what, or else just charge $10/month for access.