This one surprised me a little. Going through a pile of test equipment, I had a couple of boxes marked 18179A on the front. There were two of these in different flavors: The 18179A covers the front of the HP 4952A and 4951C
These are ancient, obsolete test equipment, but still available for often <$50 on ebay. Why do you care?
Because it's a keyboard, of course! But not just any keyboard. This one has Cherry MX black switches and some very-shallow profile keys. Oh, and a spacebar that looks like about 5U wide, with a Cherry stabilizer:
The keys are really unusual. They are short, and the skirts on the sides dont even go down as far as the bottom of the stem on the switch. And they're stepped-up in the middle. AND they're different sizes! The skirts on the smaller keys (space and top row) have notches cut out to clear the body of the switch.
The dimensions of the keys: The smaller keys on the top row (and the space bar) are actually smaller than can be used on two adjacent rows. The top of the top switches and the bottom of the space bar switches are hiding under the edge of the frame of the keyboard.
The shallowness of the skirts, seen from the side:
Possibly-gratuitous shot of the model numbers of the machines with these keyboards, and showing that these are Cherry switches
