Would have to go to the DEC LK201 (the original keyboard for the DEC VT220 text terminal, and a slew of 80s DEC hardware). The VT220 itself is a cool piece of hardware, but the keyboard is incredibly disappointing. At first glance this keyboard seems like it would have a lot to offer:
* It's as big, heavy, and sturdy as an IBM 1391401. I've seen dozens of these and never found a bad one (plenty of bad cables, though. They use a phone handset cord, and the plastic retention clips get broken off all the time).
* At least on the older ones (Mine is from '86) it has beautiful doubleshot spherical top keycaps. Later ones look like dye sub to me.
* Linear, mechanical keyswitches. (I've seen some people claiming these are rubberdome, I've never seen a rubberdome 201 but maybe later production was. The LK401 and other 4xx boards like the DEC layout PS/2 keyboards were incredibly stiff rubberdomes with laser-engraved keycaps.).
However, those keyswitches are terrible. The 'switch' looks like a spring steel tab inside the plastic housings that the keycaps snap onto. They're very stiff, very low-travel, and quite bouncy. I like my VT220 but rarely use it because of that atrocious keyboard.
