Rik- I've been looking at Quiz Wiz Challengers on ebay. I decapped the chip in Quiz Wiz, and it's not a microcontroller, just some logic that scrambles the question number using the cartridge (which is just some traces on a PCB). I guess they programmed that logic into the TMS along with the extra features.
Unfortunately, the TMSs in your pics are E and G revisions, so not currently completely dumpable. But seeing what's inside helps. Datasheetarchive has several Hughes LCD controllers, but I didn't see 0530.