IMO the Tent design is going to become obsolete with the arrival of WebRTC. With WebRTC, there is not going to be any reason to have servers running, as long as some of your friends are online. You can do everything by using public key cryptography and store-and-forward. You can authenticate with SRP/zero-knowledge password proofs. You don't need to have your private key with you, you can recover it from a quorum of your friends. Combine this with a public status/"who's online" server - could be any XMPP/web gateway for example - for bootstrapping the initial connection, and you can log in from any library/internet cafe computer. You can use broadcast encryption to address the privacy concerns of store-and-forward designs.
I wrote a series of blog posts about how such a system would work: http://carcaddar.blogspot.ca/search/label/ClearSky