[puns]

Good point, but you don't necessarily need this input device to be in your pocket, and it doesn't have to come in the form of a phone. For example, here's one solution: accept/decline calls right from your headset without taking the iPad out of the bag. Perhaps the headset will tell you the caller id when you press a certain button so you can choose whether or not to take the call. Dialing can be done through voice as well, or take out the pad and make the call using the touch screen.

[stcredzero]

Not going far enough, either of you! Why not make a Skype peripheral, but operating over Bluetooth and not USB? It wouldn't even need a fancy display. Let a headset take care of sound and the anwser button, just take care of other input/display tasks. A commodity display from an old cellphone would do the trick, and these must be dirt cheap by now. You could probably get the button count down to 6, which is what it is for the Apple Remote. The components would be dirt cheap. Margins would probably be very handsome at first. Make it the size of an old PC card. It would sell like hotcakes!