There are 4 Midget Mustang MM-1 aircraft on the U.S. registry that TailWiki has a page for. Every one is built from the public FAA record — year, serial, engine, home base, and registration history — and owners and pilots add photos, trips, and stories on top. The ones listed here were built between 1967 and 1971.
N7178
1971 Midget Mustang MM-1
Wichita Falls, TX
N77RK
1971 Midget Mustang MM-1
Barnesville, GA
N131D
1967 Midget Mustang MM-1
Perry, GA
N31CH
1967 Midget Mustang MM-1
Fayetteville, GA