There won't one day be stock like a switch. As demand and supply converge, you'll begin to occasionally see Wiis at first, and then you'll see them in more and more stores as people who have been waiting for stock begin to get them without extra effort.
There should be a pretty long convergence between "very hard to find stock" and "stock readily available everywhere" because there are a lot of people who want the system but won't put any special effort into getting it. So they'll buy it when they see it at the store they normally frequent.
Here in the US people who are willing to call around daily are still having a very difficult time finding the Wii. Demand is very far from being met here. If demand and supply even begin to converge before Smash comes out, that will all be reversed very quickly.
