You're probably right about being able to do it in an FPGA, but I was thinking more along the lines of the various clone boards out there for things like the MSX and the ColecoVision. (There's also Apple II systems, Commodore 64s and I believe an Atari 800 clone now available for people to build).
An example of what can be done is the
Omega MSXII Clone.
We could all have our own Laser 2001!
I can dream, can't I? I have some extended holidays coming up. I might try and put the existing schematics into KiCAD as a beginning point.
Chesh