Nintendo have patented the controller seen above in the image, if you wondering what the empty space is in the middle of the controller this is what was in the patent about it:
An X button 46 and a Y button are further arranged in line on the upper surface of the housing. An imaging information arithmetic unit is provided at a front end of the housing in a longitudinal direction in such a manner that an imaging device thereof is exposed from a front-end surface.
The patent seems to have been filed in February 2008 and can be viewed here: appft1.uspto.gov/
So what exactly is this controller? Is it for a new system or handheld, maybe an addon to the DS Control System or even the WiiMote, will Nintendo explain to us at E3?