Neogaf supposively has a copy of the new Famitsu and some pretty interesting info has come out of it. The most entertaining of which being this:
New Wii colors launching packin with Smash Brothers on 1/24.
* Price: \35000
* Red, Diamond Black, Mint Blue, Snow Pink, Famicom colors (limited edition set)
* Packed with two Wiimotes, two nunchucks.
Super Mario Kart Wii
* 2/28, for \5800
* Up to 8-player multiplayer
* Bikes, animals also ridable
The only thing that looks iffy to me is that there has been 12 player online confirmation in the U.S. So, I don't know if it's different for Japan or if they're talking about just one console but remember all of this is for Japan in general.