I don't see hosting as being an real issue. With the event of DSL, Cable, et al, I am sure that many project members would be willing to setup a staging area and a production area at home. I would gladly do it on my own machines, but if you try tracerouting any site in Brazil, you'll see that the backbone just makes in inviable. :o/ The offer still stands though. I can spare some space on my P200 (currently running SuSE Linux 6.4 and serving as a firewall / gateway).
What would we need? A dedicated box or just the usual Apache/FTP/SSH/MySQL combo?
What I find hard is pointing out (a) project manager(s). The manager job alone would probably be harder than the coding work.