The solutions to this are either a folding screen (not sure how feasible this is) or video glasses. My preference would be for the latter. I was reading the other day about video glasses that can be seen through, but have a small screen near the eye. The article suggested that this was equivalent to looking at a 42" screen. Sounds good to me.
My video glasses would be part of a bluetooth two-ear headset that allowed the glasses to pivot up onto the head for when you just want to listen to music through your headphones. The phone would still have a screen for normal functions, but would largely live in my pocket.
The question is, how do you control the computer when you can't see your hands (without extensive eye refocusing) and you don't want to carry around a keyboard and mouse?
Mouse function: I think a ball with motion and pressure sensors would do the trick. You rotate the ball in your had and this results in mouse motion on the screen. You squeeze the ball and you get a click.
Keyboard function: Perhaps some motions sensing gloves that would allow you to type in mid-air by showing you your fingers relative to a keyboard on the screen.
Handwriting recognition: The phone would be a palm-sized pad that corresponds to the dimensions of the screen in the glasses. The position sensing of the stylus relative to the pad moves the cursor on the screen. Touching the stylus to the pad is equivalent to a mouse click. Doing the same whilst pressing a button on the pad (or stylus) is equivalent to a left mouse click. Writing on the pad translates to text on the screen.