This is an overview of legendary Lisp keyboards. If you know of any more, please add to the list. I have a couple myself (including the prototype below) but not the first two (I would give a $250 bounty for the golden tip, excluding the keyboard itself!) EDIT: I now have some Space Cadet guts!
The Space-cadet keyboard



From Wikipedia:
This keyboard was originally designed for the Plasma Fusion system, as well as MIT LISP machines. It was sold with the early commercial LISP machines, such as those from Symbolics.The space-cadet keyboard is a keyboard used on MIT Lisp machines and designed by Tom Knight, which inspired several still-current jargon terms in the field of computer science and influenced the design of Emacs.
This is probably the most legendary and well-known Lisp keyboard, it still pops around regularly on programmer's forums and social networks aimed at geeks. Good name!
More info and pictures here.
The Knight keyboard

From Wikipedia:
See also here for more information.The Knight keyboard, designed by Tom Knight, was used with the MIT-AI lab's bitmapped display system. It was a precursor to the space-cadet keyboard.
Much less known, it started with this keyboard. Apparently Tom Knight is still giving class as a college professor. I once mailed him and inquired about the keyboard, but unfortunately didn't get a response. Later, by pure accident I was contacted by one of his students who saw my collection, and he told me Tom had two Knight keyboards hanging on the walls of his office.
Symbolics 364000


The older of the Symbolics keyboards. This keyboard is interchangeable with the later versions (PN 365407), it just looks less "metallic". It has the advantage of a cable which unplugs at both ends, which makes it easier to carry about and stack away.
See here for more information, here for inside pictures.
Symbolics 365407
The newer of the Symbolics keyboards. Comes in three revisions, A, B and C. Rev C had LEDs in the Caps Lock and Mode Lock keys, earlier revs did not.
Rev A:



Rev C here, insides here.


The Racal-Norsk KPS-10 Lisp Prototype Keyboard
Racal-Norsk was a UK company, a symbiosis of British Racal Electronics and Norwegian Norsk Data. The objective was to make a multi-user Lisp Machine. I got the prototype from someone who was working with Symbolics system at the time and was press-ganged into working at Racal-Norsk in lisp software.
They built a Lisp Machine based on the Norsk Data multi-port processor (ND-570 and ND-550) and MIT ZetaLisp (circa 1984/5).
The keyboard is probably the only one of its kind. One of the people who was working at the company at the time was Richard Stallman. Peter Richards was involved in the design of the keycaps. The objective was to make the ultimate lisp I/O experience, but this was the first and last prototype.
At the very time that the first Lisp image came up, Racal and Norsk pulled the plug on the company and fired everyone. The project was moth-balled and presumably sleeps in some dungeon to this day. It could have been something significant, and a ~20 man team worked away for 2 years to create a formal specification of MIT Zetalisp (for many the grand-daddy of Lisps). Racal-Norsk bought the worldwide rights to MIT Zetalisp outside the USA.
The yellow nature isn't the tradional yellowed plastic from sunlight, it's the nature of the prototype material.







More pictures of the prototype here.