Mozilla themselves maintained the Power Mac Firefox. I appreciate the effort, but they never had anyone on their staff particularly adept at the architecture, and Apple was busy with Safari and WebKit. Camino will abandon PowerPC with "Camino 3.0," whenever that is (their post-Gecko release).
As far as Classilla, I've been asking for developers for years. No one has stepped up to the plate. We do have localizers, and that is something, but I'm pretty much the only person writing code.