Marking a thread "un-read" after editing a post

[Abomination]

If a user edits a post is there a way to mark that thread "un-read" without posting to that thread?

Example:
If someone edits one of their posts and wants to draw attention to that, they add a new post "I edited my previous post for clarity" which will mark the thread unread and will bump the thread up to the top.

Is there a way if someone edits their post that it could be made "un-read" without adding an additional post and not bump it to the top of the threads?

The vBulletin.com site said that would require a modification of some kind and I should look here on the vBulletin.org site.

Help?

Could someone give me a clue what I would be looking for, or what search terms I could use in the search box? Or maybe a standard plug in that I have not found yet?