Right now I cannot see a week where there isn't at least a hundred thousand Wii consoles on the market. The console isn't completely sold out, and if the demand was there people would have snatched every last one up.
Casual consumers don't go hunting as much as they seize the opportunity. They are not put down by deferring a purchase another week, or even another month. There is this perception that the only thing stopping Nintendo from selling half a million units every week is the fact that they do not have them on the shelves. I seriously doubt any console will sell over a hundred thousand a week in North America for a couple more months.
So, you seem to be saying that:
1. The Wii isn't "sold out" because if it was there would not be any places with stock, but there are some areas that have stock.
2. Casual gamers are the Wii's main customer.
3. Casual gamers will not go out of their way to seek out an item but will snatch it up if they see it.
It seems to me that point 1 is in complete contradiction with points 2 and 3 together.
Even if I am mistaken (and please do explain how I am in that case), based on your points above I would have to logically conclude that there IS in fact a Wii shortage, at least as far as the Wii's main audience is concerned.