Well, it is kind of hard to make Bitcoins by leaving your investors money in Bitcoins. Of course he doesn't have them.
If he's arbitraging, which recent price moves seem to indicate, he's trying to take advantage of every other exchange basing or postulating their prices based on MtGox, which *could* backfire on him, but it is likely he's got enough in reserves that he could pay them outright and then pocket Vandroiy's bet and be at least 5000 BTC richer, on top of whatever profits he made minus the 3% interest he was paying.
I guess the question is, is he going to want his profits of BS&T in cash or Bitcoin? Recent price moves (despite what you may think) suggest BTC. He seems to be manipulating Gox while accumulating elsewhere, perhaps some via GPUMax, some via other exchanges.
It is probably more likely he sold till he found his buy-side counterpart on MtGox, and is now purchasing on other exchanges if he's actually arbitraging.