Hey, now THAT's a great idea. MiniMigAGA form factor re-worked for existing models! Me likey!
All of the extra real estate could be used for additional RAM slots, etc. Mmmm...
The idea isn't to make a MiniMig that was in an Amiga motherboard form factor. There simply isn't even close to enough people to have that make sense. The idea is to have adapter cables that will allow you to put a MiniMig that ISN'T in an Amiga form factor inside of an Amiga case. If someone figured out the keyboard connector, and figured out a way to get the SD card up to disk drive, there is no reason that a current MiniMig couldn't be installed in an Amiga case. I'm kind of surprised that no one has made a kit for that, and for installation in a standard PC case.
With a market as small as this, being able to use the same board in multiple form factors with only a couple of adapters can mean the difference between doable and not doable.
Today, it would probably make more sense to make adapters for the RetroReplay since it will already be set up for a PC.