This project has been a multi-year labor of love. I haven't had much time to work on it since last year but it suits this challenge to a tee.  I'm combining a retro Z80 with peripherals emulated on a modern AVR microcontroller to run CP/M, MSX software, ColecoVision games, and more. Check out the linked YouTube video for an overview and peruse the project log for the history of the project and a lot of ideas for what it can do.