Hi Power58,
I don't know it this may be what your looking for, but several years ago (1996 to be exact) I designed some Z80 based micro systems for use on some projects that I was doing.
They have a 32k RAM, a 32K ROM, 2 x 8255 PPI's, an RS232 interface to link to the PC a watchdog re-trigger system, and a few other bits and bobs etc.
I can 'scan' (whats left) of the circuit diagram, together a few photo's and email it to you if your interested, I should also have most of the project code available to give you a starter.
If your interested, you can have one for just the cost of the postage (they are just sitting here gathering dust).
It may save you the effort of putting some of the hardware together if nothing else.
Let me know
Roy