And speaking of HP LX palmtops, here's my 100LX. Yes, that's Windows solitaire, not even the WinCE version. This device is in fact a PC XT disguised as a 90s PDA, and it can run Windows 3.0.
@ari Actually a few weeks to a month on 2 AAs depending on usage. The processor is a low power CMOS 80186 and the hardware is generally optimized for saving energy. HP was very good at that, an HP 48g calculator will run for years on 3 AAAs, compared to maybe one year on 4 AAs on a TI-83.