Rest assured that whatever the number is, it won't represent what Wiifit could have sold had supply been unlimited. It is sold out across the U.S. and retailers are back to putting signs in the window to try to cut down the number of "do you have any wiifits?".
Honestly, I'll be surprised if the number goes over a million simply because of the manufacturing and shipping logistics of moving that many boxes. I guess we'll know soon, eh?
I hate trolls.
Systems I currently own: 360, PS3, Wii, DS Lite (2)
Systems I've owned: PS2, PS1, Dreamcast, Saturn, 3DO, Genesis, Gamecube, N64, SNES, NES, GBA, GB, C64, Amiga, Atari 2600 and 5200, Sega Game Gear, Vectrex, Intellivision, Pong. Yes, Pong.