I read your post and had a thought-Why dont you sic a collection agency on him? I did a quick web-search and found the following link:
http://www.highland-collection.com/
This outfit takes a third of what they collect-So you are not really out of pocket-and they will chase him through letters and phone calls. Wouldn't it be kind of fun to know they are harassing the heck out of him? Would you give 35% to recover 65% of a debt which looks uncollectible right now? I would.
If you need to locate him and can't, pm me and I will turn you on to a little tool that will put you right on his doorstep-you'll know exactly where he is.
BTW, cant vouch for any of these services, but may be worth a try.
As always just my humble opinion.
Later