[kwdc]

Now put a raspberry pi in there. Emulate the cpu etc. This approach worked for the 68k, eg PiStorm.

Or perhaps put in a FPGA...

Don't even necessarily need it to be an x86 emulator. Use the motherboard as an oddball I/O facility. An ARM machine (ab)using ISA cards would be an odd duck. Throw in a software x86 emulator with a bridge to the ISA bus for added compatibility. Of course there are simpler ways...

All that said, I'm not sure exactly what the benefit really is other than having a cool project. But thats maybe the point. Maybe that's enough in itself.