If Mt. Gox owes you money, here's something you can do easily. The SEC says Bitcoins are an investment contract, and a judge has agreed. That means the SEC has jurisdiction over Bitcoin broker/dealers.

File a complaint with the SEC against Mt. Gox, for their defaulting on customer funds withdrawals. (Click here to file a complaint.) Do your homework. Get the street address of Mt. Gox in Japan right. Get the company name right. Make the point that they're months late on their cash payments to many customers. That's a huge red flag to the SEC.

The SEC does go after unregistered foreign broker/dealers dealing with US customers.  Such dealers have to register with the SEC if they deal with US customers directly and hold customer funds. Mt. Gox has a legal U.S presence; they have a registered agent in Delaware so they can file with FinCen. Mention that address in the complaint.

If you file a complaint, a copy goes to Mt. Gox, sent by the Securities and Exchange Commission. That will get Mt. Gox's attention. They have to answer the SEC. You'll probably get paid very fast.

Just because Mt. Gox is in Japan doesn't mean the SEC can't fine them. Also, the US SEC and the Japan Financial Services Agency have a formal cooperation agreement. If the SEC tells the FSA that Mt. Gox seems to be in financial trouble, the FSA will be interested. The FSA has the authority to audit Mt. Gox any time they want to.

You don't have to put up with Mt. Gox's excuses. You can drop a big hammer on them.