An interesting discussion to be sure. As far as cloud based access go, off the top of my head both Oregon State and Nimbix give access to P8/P9 instances for developers, free or cheap.
One of our members, Raptor do a nice high performance dev workstation, pretty sure they do everything from a mobo+CPU combo to complete systems.
I think lower end than that might well come, we certainly see it as something we'd like to facilitate through the OpenPOWER Foundation.