This page is a photo gallery of lisp keyboards.
One of the first Lisp Machine keyboard, called Knight keyboard.
Photo and some info from Knight (TK) keyboard @ http://world.std.com/~jdostale/kbd/Knight.html.
The Space-cadet keyboard came after the Knight keyboard.
Here's more photos of the Space-cadet keyboard, a brand new one, partially disassembled.
Photos of the Space-cadet keyboard by webwit @ http://deskthority.net/viewtopic.php?p=23509. Used with permission.
For the key layout, see: Lisp Machine Keyboard Layout
For lots more photos of the space cadet keyboard, see: https://secure.flickr.com/photos/obra/sets/72157635353286814/
Thanks to Jon Snader for tip.
This model comes after the Space-cadet keyboard.
This model comes after the PN 364000, and is compatible to it.