To be honest, I would just get a cheap x86 laptop with a USB port and
use a USB<->RS232 dongle.
How is this an improvement on using one of my many portable machines with
built-in serial ports (and indeed terminal emulators/kermit in ROM)?
I already use an HP95LX palmtop for this. OK, it's limited to 512K memory
unless I stick a card in it, but that's plenty of space for classic
computer-related files :-)
-tony