Tomasz Nowak is developing a system that makes it possible to run 16 virtual C64's inside 1 real Commodore 64. The extended memory is divided in 16 block of 64 kB (16 virtual machine), 0.5 kB RAM for program MMU, and 16 memory blocks for the VIC, CPU, zero-page and the hardware stack.

Demonstration video of the 1 MB Commodore 64