Z80!  A real blast from the past there.  Did Zilog ever make a
    controller with that instruction set and microcontroller features?

Yes, the 64HD180, or something like that.  Nice processor, covered pretty
extensively in Circuit Cellar over that last dew years.  I believe it was
only done in relatively full-blown versions - 48 pins up, with built in bank
switching and dram controller, I think.  CPM on a chip, a little too late.

BillW