How about re-funding Persona then!
Manu Sporny's videos, as usual, are a very nice introduction:
Some of this grows out of the needs of the web payments group, which has some of the same people. The credentials specs have not totally solidified, but are getting there, and are growing out of some real implementations that Digital Bazaar are working on.
By the way, the "linked data signatures" bit has a small amount of controversy in "why not JOSE"? It's something I'm in the middle of reading up on and trying to understand.
At the very least, I think the work coming out of the credentials group may be a good path forward for the kind of future we're trying to build in MediaGoblin and related work.