I see this thread died off in November but figured I would drop notie of my experience with TH.
I was one of the many customers whose bitcoins vanished without notice when Tradehill shut down two years ago. After an email sent to the support@tradehill address, Jared Kenna answered me quite promptly verifying the amount owed to me and asking me for a wallet address he could deposit them to. I immediately responded with my wallet address and thanked him for his business.
Weeks and months went by without any news about my coins. I started emailing TH support 3-5 times a week asking for the status of my coins without receiving a response. Eventually, after 5 months, I sent an email threatening legal action. Surprisingly, my coins were returned and Jared Kenna contacted me again to verify that the transaction had gone through properly.
It was a long hassle but ultimately everything got straightened out.
Yes, litigation works in these situations. Even threats of litigation sometimes work.
There's a whole system out there designed to deal with people who take the money and run. There are business called "skip tracers" who specialize in finding people who ran. Lawsuits where they just refuse to pay up are usually not very complex or expensive.