When I wrote this, I'm not sure if the iPhone had been released; certainly at that point if you were carrying around something computer-like in your (large :) pocket (more powerful than a PalmPilot) it was something like a Jornada http://en.wikipedia.org/wiki/Jornada_(PDA)

This sort of form-factor came directly out of things calld "palmtop pc's" like http://en.wikipedia.org/wiki/HP_95LX

To me "palmtop" strongly connotes something handheld, with a clamshell or a slide-out keyboard, and running a desktop-style OS. That HP 95LX is a good example; the OQO was a more recent one (2005 ish?).

A device with a similar form factor but running a mobile OS would have been called a "MID" (mobile internet device) or possibly a tablet - https://en.wikipedia.org/wiki/Nokia_770_Internet_Tablet for example.

Palmtop is typically used interchangeably with PDA.

How about an IBM PC-110?

http://www.basterfield.com/pc110/pc110idx.htm

like "lap top" but it goes on top of the palm of your hand (at least that's my revisionist version)