I'm hacking around on a distributed version control project, and I think I've found a cool solution to this problem.

I've created a github gist with my public key and a signature. Now people can see that gist and verify that the keyholder posted the signature via my github account. People can fork the gist and put their own signature in. Now I can easily list the forks of my gist and get a list of public keys that are cryptographically linked to certain github accounts.