This isn't so much a request as it is an idea.
Why not make a thread voting system? Users can thumb it up (just a preference, can be called upvote, or 'like', etc.) and the thread OP could then receive reputation from it.
Just a thought.
Thread rating can be use for the same purposes. Instead of an isolated plugin, just an small plugin which fetches most Rated thread(s) and gives the reputation to the Author.
I just think thread ratings are all-around terrible, and is just a bad idea. The vast majority of threads are rated either 5 or 1, and it's too much to think about for the average user. You don't see the fb like buttons being replaced with 1-5 stars, and such. If anything, it should be something like this (did this in 2min):
http://i.imgur.com/PcodW.png
I did this really quick, and to be specific, the system would work by having the default points at 1. There would also be downvoting but a thread can never go lower than 1. Simplicity is key.