I have completed updated the schematic. The board went out to FAB today. I am using EasyEDA for schematic capture, board layout and PCB Fab. I will mark the project "Public" when it is stable.

Minty Z80 is a system with virtualized I/O and minimum component count in an Altoids Tin.
It appears that a ATmega1284P could be used instead of the ATmega32A and get more memory and a second serial port.
I imagine that there is enough RAM to store a disk image of a CP/M disk with a few files like MBASIC, ZORK, STARTREK, etc.