If you've dealt with this guy before then you know where he lives right?
I'd be giving the police a call! If there's two of you guys that've gotten screwed then surely they have to act on this?!?!
This is exactly why I keep a copy of all correspondence with sellers/buyers until I know everything is ok - if something goes wrong then I have the entire sales history 'on paper' to back me up, not just my word vs theirs...
I feel sorry for you guys, I got screwed over $1k on a Marshall back when I first joined eBay, I'm really much more cautious since then, but I still worry!