I agree with Tanktalus that putting a troll's name in lights is what they're after. (I'm reminded of Luke in Mos Eisley confronted with someone saying, "I have the death sentence on twelve systems" as if this is a prize.) I generally agree also with tye in Re: Discourage Trolling (effects)—highlighting doesn't do much good. It's tempting to try to find a way to show trolliness without the trolls being able to claim the prize of trolliness, but that seems contradictory right away.

My only thought was to put the big red flag on the "Comment on" page when someone goes to reply to the troll. However, considering all the other succulent clues on that page that are routinely ignored by users most needing those clues, I'm not convinced that another helpful hint will be heeded either.