I'm thinking about putting this on the SD cards I use in my cameras. It is a Trojan that will identify the user when it is used in someone's computer. Good way to get my stolen camra's back ;D bad for privacy >:(
http://www.gadgettrak.com/products/usbtrak/faqs.php
That would be around $60.00 a year for me.
I've had 5 stolen from my house and 3 taken from the woods.
Sounds like you really need it.
Here's some discussion on it.
http://www.chasingame.com/forum/viewtopic.php?f=11&t=12269