meh, still calls rebuild_topic_data, so we'd probably either modify that function or give it a helper function.
i'm ok with that. makes a lot of sense to use one routine or routine + helper for both.
what i really would want at some point is to join the bodies themselves as much as can be. prime example is PMing a user on topic move/merge. right now one body does it, but the other doesn't and if we keep adding ancilliary stuff to them, it would be wise to get as much in common as possible to begin with.
