The Nintendo Wii is still a hard find in the United States. There seems to be no Wii supply problem elsewhere, just in the U.S.
Wired reports that a Wedbush Morgan Securities analyst said this week that Nintendo plans the largest marketing campaign in the companies history to promote Wii Fit. Along with the campaign Nintendo is supposed to increase the monthly Wii supply by 150,000 consoles.

The Wii Fit release is on May 19th. Comments made by Gamestop this week put a big question mark on the analyst statements. Gamestop sees the Wii supply shortage continues for at least another 6 months.

I hope Nintendo will get finally around to satisfy demand for the Wii in the States like it does for instance in Germany, where I can go right now to Amazon and order a Wii console for the normal price of 248,95 Euro.
Because of the weak Dollar, this Euro price is actually about what the marked up Wii consoles sell for on eBay and on Amazon.com 3rd party channels in the U.S.:~$390. I am actually not sure what I should think of that "coincident".
Nintendo is not benefiting from the mark-ups. The money stays in the channels with wholesalers.