In an acceptance speech, Miyamoto casually mentioned he's working on a new piece of hardware, as well as a new MotionPlus-enabled game.
If you remember my initial skepticism when it was rumored Nintendo would be unveiling a new piece of hardware at GDC 2010 next month, I said it could be one of three things: a proper North American unveiling of the DSi XL, the Wii HD or a new GameBoy. Well, no specifics were given in Joystiq's article - not even a quote - however, this can lead speculation that the DSi XL is not the topic of GDC, however, if it's not not the DSi XL, the Wii HD is continuously downplayed, and the GameBoy was killed by the DS, then where is there to go from here?
Me? Well, I believe it's completely unrelated to the DS. Why make an announcement about a new handheld when the newest unveiled one isn't even out yet? The DS was supposedly the third tier of Nintendo products (sorry, but no, it's not; Nintendo successfully killed the GameBoy with their own system), so I'm going to say it's Wii related. Nintendo doesn't do hardware refreshes of it's main systems (that is, unless, you count the slimmed down NES and SNES they released, and that was about 500 years ago), so it would be contradictory. Then again, Nintendo was the company that pioneered pack-in games with Mario on the NES, and nobody has done that at launch except for Nintendo themselves with Wii Sports.
Final thought: Wii something. Break out the scorecards, people. GDC is going to be very interesting.