Someone has listed a bunch of
black Affirmative 1225T's
here on eBay for $20 each + shipping.
These of course are modeled after IBM Model M/F 122-key terminal boards. My understanding is that the "T" in the "1225T" part no. means "tactile" and indicates they're buckling-spring boards. At this writing, 9 more are available.

These are supposed to be compatible with normal PCs, though you probably won't get the extra F-keys to work without special software (e.g. Soarer's), and there may be issues using them with standard PS/2-to-USB adapters. (There are some GH threads on Unicomp 122s, or maybe someone would like to clarify here.)
Some of you may think it'd be a better idea to buy an actual Model M 122 for around the same dough. If so, fair enough. But these are less common than un-rebranded Unicomps, and I know some of you drool over black cases, so there you go.
Oh, and if you want a new one,
you can still buy them for $139.