To my understanding of US tax laws- If you earn money, it needs to be reported. If you make a tidy amount selling widgets for BTC, you'd need to report that income- Just as if you would report money earned in a foreign currency. (Especially if you then exchange the BTC for USD to buy food/pay bills/buy jetskis).

Even if BTC is not considered an actual currency, it's still a possession of some value- and I know at some point they ask about that. I've seen someone claim that 'BTC only has the value that's assigned to it' but that's true of well, everything.

I'd talk to a tax accountant about, if you have a decent sized wallet. Better to consult on it once, then muck up and look at fees and penalties.  I'm not going to assume it falls through a loophole just because I really want it to.