it takes about 200 $k to hit 5 $ at the moment. There are enough funds on MtGox already. If people decide to have fun holiday trading,and have BTC before masses add funds to MtGox in the new year, we may hit 5 $ soon:
Guess: Dec 29, 2011
That's true, but on the other hand, it would only take a dump of ~50kBTC to take the price down to $3. We've seen at least a few people trade around that volume in the past month or so, so I don't think it's an unlikely possibility that somebody could cash out. In fact, IIRC, somebody bought 40kBTC or so at $2.9. That person could drop the price down to right around $3 and make a pretty nice profit right now.