Revisiting this thread after 5 years. https://twitter.com/plgDavid/status/1270410663840681985?s=20
Recently designed a MC6809E ICE for various purposes including this one, and put it to test this week.
[/img] (picture shows it on a Bally Sente main board for a test)
New findings: It appears the address map banking is more complex that originally thought. Currently figuring it all.
Other good news. I stripped the m6809e core from MAME, ran it on my STM32 on the ICE, and can get the same results as when I put an original MC6809E in.
So I dont know if there are instances of MAME cores used to make other MAME cores, but I thought this was funny.