Love the show - Ben and Karen make a good team.
Liking the work they did on the ZX Spectrum, how about doing somthing with the Amstrad CPC?
It's a Z80 machine and uses an external monitor so no PAL/NTSC problems and can use a SCART.
There is also a Gotek for USB sticks and an SD card reader for the Plus cartridge models plus custom software to avoid keyboards...
Would love to see what Ben and Karen could come up with and I can advise on what to get...