Nope. Well, no more uncomfortable than working on a laptop without an external monitor ever is.

Merely taking my hands off the keyboard is enough for them to move out and away, since I have to "swing" them in to use the keyboard to begin with. This leaves them inches from the screen in the best case, and nowhere near the computer in the worse case.

Apparently not. My father got a HP netbook/tablet and feels super comfortable with it, scrolling and zooming in with gestures on the screen. I never thought it'd be comfortable (for scrolling I'm super used to the mouse wheel, a habit he never caught), but to him it came naturally and he certainly wants it on any other device.