My favorite is still the Tandy 100 family. At one point I had a 100, 102 (the best one IMHO), the clamshell 200, and a WP-2, along with the disk drives, tape drive, acoustic modem, some fancy ROM upgrades, etc. I also had a couple NEC look-alikes and a weird Epson version with an even smaller screen, built-in micro cassette deck and built-in receipt printer. Sadly I had to give away the whole collection when I moved, I just couldn't justify lugging them across the continent!
These were great fun to dink around with in BASIC, messing with com stuff and dabbling in packet radio, pushing the limits of the graphics for games, ordering experimental ROM chips from the back of magazines, and even just writing on a decent keyboard without worrying about battery life (4x AAs would last a loooong time!).
I still keep an eye out for these at garage sales, maybe some day I'll start rebuilding my collection.
It doesn't fit on your palm but it's still old enough to be called "vintage"? Then it probably belongs in here...
I used to have one of these and always tried to justify using it by finding a way to program a killer app. Best i could come up with was a database for my VHS collection. Which honestly was not so much ahead of a sheet of paper. XD I always hated these for the display, so I'd be curious to hear about ways to pushing the graphics to the limits since i never managed to do that. I had a C-64 at home and always thought like "the graphics suck so much on this one". But yeah keyboard and battery life were great.