I think a PiPad should look something like this. There should be rather liberal 2cm rounding in the cornels, and the Pi itself should be in a compartment inside the pad, such that the ports can be plugged in when needed. if the wirings allow it, cpu-board-popup design of sort maybe?
Didn't spent much time with the picture, as I'm not a mechanic engineer. Someone else should implement this definitely.
Edit: seems I'm repeating myself, but I do think there's merits in this kind of design. The model's bit too thick perhaps, but anyway the thickness should include the card entirely. Also thought the LAN and USB could be always exposed, as they are most commonly needed ports there, after audio and composite. But then maybe when it's attached to something, you'll need all the ports anyway.