Hi Evan, and welcome.

I can't answer your question about sourcing in bulk, but I would like to give you encouragement in your project. The PRISM issue has been gaining much attention recently, but really the problems of privacy invasion and general loss of personal freedoms through service centralization have been getting worse over many years, and projects like Eben Moglen's FreedomBox and various privacy networks have been appearing to fight it.

Both Raspberry Pi and BeagleBone Black (BBB) have a price sufficiently low that decentralized solutions for social networking and for all other Internet services no longer have a significant price barrier. Anything that encourages people to get out from under the centralized control at places like Facebook and Google+ and Twitter is a good thing, not only for them but for the health of society generally, because doing nothing just leads society ever closer to a corporation-led 1984-type scenario.

Where we're currently heading is the exact opposite of the IETF's Mission Statement, which encourages interoperability and massive scalability through decentralization and federation of Internet services. Instead, the megacorps want complete centralization, block federation at every opportunity (Google recently blocked federation in their XMPP Chat), and continually create proprietary enclaves like app stores instead of defining interoperable services that anyone can federate. The technical term for this is "bad".

I'm looking forward to seeing your solution, although I'd want to see it not on R-Pi but on BBB, as this board is in the same price niche but works better for networking.

All the best!

Morgaine.