Dennis Ferron built a laptop with a 6502 processor. The system is built with a Parallax Propeller micro-controller and a real 6502 CPU. For the case he used a toy laptop and a the screen is from a portable DVD player. The Propeller handles all the I/O for the 6502. The 6502 can access the 64 kB of memory. But the Propeller decides what that memory will be, it can be RAM, ROM, a disk controller, a input buffer etc.