Sweet Jesus.
It'd be worth your while finding the guy and getting them back or offering a bounty of half your recovered coins to someone? Heck, why not create a thread and offer that bounty here. I'm sure someone looking for up to 3000BTC would be happy to do it.
We have tried that offering significantly more than 50% (for either Trendon Shavers or Sam J Theofanopoulos). No-one bites. If you are interested I'm 100% certain we can come to an arrangement.
Finding him is probably the easiest part.
Getting the Bitcoins out of him legally might be more difficult.