Well, I thought of this myself, tried it out, and it worked!
Ok, so what you do, is go to an account trading/buying/selling website such as Markeedragon. Find someone who is willing to trade, and give them a link the the person you dont like's armory. If they are interested, tell them to give them a whisper ingame about the transaction or w/e. Hopefully, the person from MD will get pissed at stuff, and then talk to you, saying that that's not your char. Try and convince him that it IS your char, and then hopefully he will believe you, but think you are a scammer, thus reporting the character. If done correctly, then a GM might ban the person!
I have tried this, and it worked. I guess it all depends on the people you work with.
Thanks for your time, and please don't flame!