For the ranks:
http://forums.bukkit.org/threads/admn-dev-permissionsex-pex-v1-17-tomorrow-is-today-1-0-0.18140/This works absolutely wonderful, although it would require someone making the file to have experience or just want to learn.
Block tracking and rollbacks:
http://forums.bukkit.org/threads/info-admin-logblock-v1-50-enderdragon-logging-tree-grow-logging-1-0-1-r1.4543/Uses SQL, and I assume CG has its own. Works like a charm.
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Just to answer some of the posts that seem to be misguided. Personally use those on my public server, which we just finished the development on. Moderator abuse isn't even
possible on my server. (>.>) Our server is pretty popular traffic-wise, and still everything is managed to remain legitimate and stuff. There are a few very important plugins that you would probably want for precautions though...