Solved, answered threads

[Bauer]

I'm looking for a plugin or product that allows mods/admins to mark a thread solved, and closes the thread.
You can see it here:
http://forums.microsoft.com/TechNet/...5650&SiteID=17

So basically everyone should be able to mark a post (or more posts) as a solution for the problem stated in the first post (see: was this helpful: yes or no/ but something like: "this solves my problem" is a more convenient phrase), and then a moderator would get a pm and he can mark it as solved, that adds a [solved]-prefix to the thread that automatically closes, with in the first post a link to the post(s) with the solution. Also the post with the solution has an Answer-prefix in green.

Would this be difficult to code or not?
I think this would be much more efficient then a thankyou button on our forum.