...IIRC from an old ssh thread, the Republic MX-773 was a proposed surface-to-surface missile with a range of 500-1500 miles, with two variations being studied: one subsonic A-model and supersonic B-model. The subsonic MX-773-A was dropped early in the program, while the MX-773-B was pursued with either a rocket or ramjet engine. The project was canned in mid-1947, AFAIK there were no prototypes built, which might explain the lack of photos.
UPDATE: Mark Wade mentions this over on astronautix.com:
http://www.astronautix.com/lvs/rascal.htm
...This was apparently part of a rather large series of postwar missle studies:
March to April 1946 - Army Air Force awards nine one-year missile study contracts. The MX-770 contract for an 800-km range boost-glide missile derived from the German A9 concept went to North American; this would evolve into the Navaho triple-sonic intercontinental cruise missile. Martin received a contract for development of the MX-771, a subsonic ground-launched cruise missile with an 800-km range; it would evolve into the Matador and Mace missiles. Curtiss-Wright and Republic received contracts for the MX-772 and MX-773 surface-to-surface missiles; they never advanced beyond the initial study stage. Convair received the contract for long-range rocket-powered missiles; this evolved into the Atlas ICBM. Northrtop received the MX-775 contract for a 5000-km range cruise missile; this eventually flew as the Snark. Bell receives a contract to develop the MX-776, a 160-km range rocket-powered supersonic missile to be launched from B-29 bombers. This would evolve into the Rascal. McDonnell received a study contract for the MX-777 air-to-surface missile; this evolved into the anti-submarine 'hydrobomb' concept and was eventually transferred to the Navy. Goodyear received contracts for the MX-778 and MX-779 air-to-surface missiles; these never advanced beyond the preliminary study stage. Concurrently, the USAAF had the GARPA surface-to-air missile project underway, which would evolve into Bomarc; the USA Army the Corporal and Hermes (later Redstone) surface-to-surface missiles and the Nike and Hermes A1 surface-to-air missiles; and the Navy a range of missile technology development projects (Regulus, Bat, Kingfisher, Little Joe, Lark, Bumblebee, Gorgon, Dove).
