Oh, I do like that. Any more info on it?
It gets a page in Hunnicutt's "Abrams - History of the American MBT". Just says:
"In late 1962, the U.S. Armor Association sponsored a competition for a new main battle tank design. The winner, illustrated in the January-February 1963 issue of Armor Magazine, consisted of two tracked units connected and operated in tandem with a two piece gimbal ring type joint. This connection permitted the two units to roll and pitch independently about the axes within the joint. Designed by Robert W. Forsyth and John P. Forsyth, it illustrated the wide range of concepts under consideration at that time. The tank could be broken down into the two units thus meeting the weight requirements for transportation by the aircraft of that time. The vehicle was to be driven by a multifuel piston engine coupled to an electric generator in the rear unit. This provided power to four traction motors driving the sprockets, two located at the rear of the front unit and two at the front of the rear unit. The proposed main armament was carried on the front unit and consisted of a 155mm smooth bore, rocket boosted cannon and a 20mm Hispano-Suiza automatic gun. Provision also was made for the installation of a 7.62mm multibarrel machine gun on the rear unit. The vehicle was manned by a crew of seven with the commander/gunner, the gunner/ loader, and the driver in the front unit and a four man tank support team in the rear. Weight was estimated to range from 24 to 32 tons depending upon the armor protection."