Commodore MEGA65 Space Computer Design

Commodore MEGA65 Most Probably The Best Computer
The 21st century realization of the C65 heritage: A complete 8-bit computer running around 40x faster than a C64 while being highly compatible. C65 design, mechanical keyboard, HD output, SD card support, Ethernet, extended memory and other features increase the fun without spoiling the 8-bit feel. Hardware designs and software are open-source

MEGA65 | Products | Trenz Electronic GmbH Online Shop

XEMU is a great emulator for the C65 (xc65) and the MEGA65

Commodore 65 Wiki

C65 System Specification Document

Here is some stuff for the Commodore 65, whose production was canned at the very last minute in late 1991

Secret Weapon of COmmodore The Commodore 65