One of our esteemed GH colleagues (I won't mention his handle, as I don't know if he'd want me to) is selling one of these nice Affirmative-branded (Unicomp-made) 122-key PS/2 terminal board:
Unicomp Model M 122 Key Mechanical KeyboardIt was made 10 years ago, when Unicomp still cared about print quality. ;?)
The listing says the keys are "a bit yellowed", but I think he may be imagining that; I've never seen Unicomp's PBT keys change color (and these are gray to start with).
$35 + free shipping. You can't beat that price for a real buckling-spring board in good shape. I'd buy it myself, but I've got one.
Affirmative still OEMs these, BTW, and
charges $140 for them.