What other systems did they build similar to the PALM? I remember as a young kid buying a quite large (~3ftx4ftx3ft) IBM minicomputer that was just filled with those modules at a local thrift shop during the late 80s.

No keyboard or screen, although I seem to remember it had an 8in floppy drive. Its been so long I can hardly remember it, but I distinctly remember those cards with the square metal cans, many of them socketed. It had a really nice set of schematics and service manual inside the case also.

edit: After some google digging, it must have been something like a 3274 terminal controller.