You know, I'm starting to wonder if all that unused space between the screen and the central body's sides is, well, actually used. I know the rumoured details haven't mentioned anything about buttons on the body itself, but it's also true we haven't heard anything on NFC, for example. It could be under the screen itself (like New 3DS), but it could also be an all-purposes NFC/navigation button for the body itself, so there are NFC functions (Suica cards in Japan, for example) even if you bring around the central body alone.