So far, i've failed to see a reliable committee-signing trust system. Moxie's Convergence blows chunks all over my network connections in practice.

Committee depends on things like number of nodes in the network and integrity of the nodes, not to mention you can still do analysis on who was sending or receiving something at a particular time (which may not be enough to stand up in court, but it's enough for the NSA to know that Mike is talking to Jeff, or whomever).

At the end of the day, the best method currently available for clandestine activity on the internet is one-time anonymous drop boxes, and luck.