hi,
We've been working on this on and off for a while, and are pretty close to taking up user accounts now. I've started documenting the User part of things here : http://wiki.centos.org/DevCloud
There is a GUI as well, but meh. Everyone can CLI it.
This is running off OpenNebula on 4 machines, with gluster doing the storage under it. There are another 4 machines waiting to do in, as soon as we get extra power capacity at the DC it will expand ( from 64 cores now, to 128 cores ); there are a few TiB of fairly performant storage backing this entire setup.
There are no real limits for the users at this point, and unless we get lots of people being abusive of resources, we will try and keep it that way.
regards