On Sat, May 28, 2016 at 5:31 AM, Corey Cohen <applecorey at optonline.net> wrote:
  I can't wait to buy one!!!  I have a spare
Replica-1 just waiting to hook up to a Monster 6502. 
It doesn't run at full speed. It presently runs in the tens to low
hundreds of kHz.  If a Replica-1 can be run slower than normal, that
might work.  Other common 6502-based micros, such as the Apple II or
Atari 400/800 will not work at low speed due to inherent timing
requirements related to video generation and DRAM refresh.
  Just need to wire up a single step switch and this
thing will be awesome!!! 
If you wire single-stepping using the RDY line, that should work,
though it will only single-step read cycles, not write cycles.
You can't single-step the actual clock because it is dynamic logic.