There are 6 Aero Commander 681 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 1969 and 1972.
N2750G
1972 Aero Commander 681
Wilmington, DE
N2749G
1971 Aero Commander 681
Coral Gables, FL
N526WY
1971 Aero Commander 681
Maineville, OH
N681TC
1971 Aero Commander 681
Waco, TX
N29PR
1969 Aero Commander 681
Kalispell, MT
N681SP
Aero Commander 681
Labelle, FL