They're going to be flying in 360's directly from China, instead of using ships, until production ramps up and demand subsides after the Holiday season. I expect a slow, continuous trickle, until they start making them fast enough to load up some ships. Thats when you'll start seeing them in quantity.
Flying them in isn't an efficient way to move any quantity of product, but they're not making a ton of them, and they need them here right now.
Somebody needs to confirm or deny the rumor that the 360 is region free until you put a game disc in it, might be able to import them from Japan.