That law won't pass because it's complete bullshit. There are only two ways for online money to equal real money:
Either the MMORPG company themseleves sells the money (Second life)
A third party trades money for ingame money (IGE)
In either case, the company is responsible for paying any applicable taxes when the money is tranferred. They could add a 10% tax for exchange of real life money for virtual currency, but they wouldn't be able to directly tax your "assets" within the game.
Unless the SEC or some other goverment agency fully monitors mmorpgs*, taxing ingame wealth as real assets can't seriously be considered, and considering how a trillion gil is probably less than a million dollars, that would be a huge waste of goverment funds to tax something silly that they could just tax at the "counter" (ige.com)
*if it wasn't regulated, a squaresoft executive could implement a "debt" system, and put himself into a 50 quadrillion gil debt for some stupid reason, and claim no profit on his taxes.