Hmm, having Z80 support directly in FPGA would be cool (also for C128 mode, hehe) but it requires FPGA resource then for that ... Anyway if Z80 is implemented, and also have the "hypervisor traps" etc, then it also makes possible to "emulate" other Z80 based computers as well. However, I think it's a bit out of scope of Mega65. Maybe for the C128, it's still somewhat understandable to include, but I hardly believe that it will be included anyway ... It's even interesting to think about on the 65xx line: if "emulation" using "I/O trap" anything makes that possible, other Commodore machines can be "emulated" like C+4
But that's at least 65xx ...