Along the lines of the real world PITA you acknowledged at the end: getting dollars out of mtgox is a nightmare and don't expect for a second that you won't be giving up all your info to the government.

I had some BTC lying around there for a year or so. When I came back, they had upgraded their security methods to the point where I had to:

-submit proof of residence

-submit a valid photo ID

-wait several days

-ask for verification on dwolla

-wait several days

In addition, there is a disclaimer on mtgox explicitly forbidding Tor and using proxies. There's not a shred of anonymity in this process.