I hope that someone will find, or design a fully enclosed mini case for the FPGAArcade Replay board(s) with a matching back plate for the ports. Your idea for duplicating the plexiglas case like the one for the MiniMig is fine for many people, but some will want a more conventional case design.
I don't remember if anyone has asked MikeJ already, but what are the chances of running the FPGAArcade Replay from battery(ies) to make it some kind of portable device? I am not a fan of the new touch screen tablets, but would not mind seeing someone turn the FPGAArcade Replay into a laptop design with a proper keyboard & LCD.