I guess http://lussumo.com/addons/?PostBackAction=AddOn&AddOnID=221 would do half the trick, it generates a link to a search, but doesn't show the result on the actual profile.
I would rather the results are actually displayed. Can't this be don't like the search? Exepct the results are already displayed on the user's page, last 10 posts / threads
You might rather something, but you have to put in some work yourself if there's no readymade addon. Tbr has given you a place to start- try ripping that apart, along with something that displays items on the account page to combine them.