think about a plain phone, all the surface is taken by the screen (as the iphone has). there's only a button and it is used to turn on the screen by a biometrical check of user's fingerprint

then, as the screen is turned on there is a laser keyboard that comes out to get user's commands. it's quite simple and it's numerical. if the user wants he could select a special key and enlarge the keyboard

lol, quite visionary