I've attended both transparency canp and participation camp recently and thought well of them both as being low barrier and cost effective ways of kindred spirits getting together to discuss things and network.
I believe that the unconference form is evolving and there may be a family of types in the future. I'd like to help that evolution without damaging the good aspects. One thing to improve is the productivity of the last half of such meetings where people ar fired up and may be heading in several directions and one wants to harness this before the meeting ends. One thing I've seen is session reports that presented early enough to not only be discussed but to see the relationship between different sessions, some of which one may not have attended since there are simultaneous sessions.