Find Massive threads, auto lock them, then make (part 2)'s

[sross]

I recently had some woes regarding huge unwieldy forum threads grinding my db to a halt. It would be cool to have a mod that identifies such threads, locks them and generates a new thread containing the same original post from the other thread, but appends (part 2) to the title. Something along those lines. If that is a bit too much then how about a mod that lists all threads over x replies?