The TecMar 8086 CPU board S-100 was in my opinion probably the best and
cleanest designed S-100 8086 board. There were no PAL chips or other custom
circuitry on the board. Unfortunately it came out a little too late to
win wide popularity in the S-100 Community.
This board had a very clean circuit design. It had its own 8259A on board
Interrupt controller. it was designed to run at 4, 5 and 8 MHz on the
bus. It was a model example of how to place on 8086 CPU on the IEEE-696 bus.
The only thing lacking was a flexible wait state circuit for slow RAM and/or
I/O ports. It would also have been nice if it had its own onboard EPROM.
The excellent manual that came with this board can be seen
here.
It has an excellent discussion explaining how to put the 8086 on the S-100
bus.