Sure, but only up to a point. How are you going to explain how you mined a billion dollars worth of Bitcoins? What equipment did you use for that? Do you have receipts? How did you pay for /that/ equipment?

I agree with the previous reply that he might find a nation to shelter him but the US government is going to do anything they can to get at him there. Look at the success we've had in shutting down al Qaeda's financial arms and seizing their assets worldwide. If the US government can't get at his money directly, it will assert tremendous pressure on someone who can.