Welcome to VGChartz, though since you use our (ioi's) numbers you must have been a lurker for a while.
Nintendo likes to upgrade hardware? Maybe for their handhelds....but I don't think there has ever been a hardware revision for one of their consoles. Certainly they have added peripherals, but their systems remain intact.
Also...Nintendo will release an HD Wii — called the Wii2 in 2011.