That was just a posting at Gamestop's site, and that was pulled.
Here's a scan from Nintendo Power
that lists the wheel at $10. May not be the best price, but it's at least less than we thought.
Now if you still think that's too much, look at the discussion Iwata has about the game
. There are hints that the wheel is just to give non gamers something familiar to use while the play racing games.
In other words, we hardcores can stick to the Gamecube controller, or just use the Wii controller on its side. The wheel is just to attract new people to Mario Kart. We don't have to touch it.