Taxing Virtual Trade?

Via Terra Nova, Congress has finally taken an official interest in virtual economies. I wonder if this has anything to do with the recent passage of restrictions for online gambling. While this proposed study is preliminary, the wheels of regulation have begun to spin. The preliminary opinion in the Joint Economic Committee press release doubts taxation will be necessary for in-game trade. So, perhaps taxation would only occur when converting between real and virtual currencies. That seems like a likely first step. However, given the tangled web of laws we have regarding investing and retirement saving (IRA/Roth IRA are just the beginning), I doubt that for-profit, long-term investments in virtual currencies will remain untaxed for long.