According to "CROSS COUNTRY CARS from 1945" (compiled by the Olyslager Organisation and edited by Bart H Vanderveen 1975) the Mighty Mite was originally designed in 1950 by American veteran racing car driver, Ben F Gregory and initial prototypes were built, as Dave said by Mid-American Research Corp at Wheatland, Pa.
Production models did change somewhat to the early proto's.
According to the "MILITARY VEHICLES Directory from 1945" (edited by Bart H Vanderveen 1972) it's competition came from a similar spec vehicle made by Willys called the Bobcat ....It looks like a tradional jeep that has been washed with hot water and shrunk to about half the size of the regular vehicle
The interesting thing for me (and that is why I know a little/very little, bit about these vehicles) is that they often turn up when people compare Haflingers to other vehicles, as they are very similar in size and weight specifications.
I find it fascinating that manufacturers can build vehicles of similar specs but that are so different in design and manufacture..... "There's more than one way to skin a cat!"
Might Mite M422 WB: 65" Size: 107 x 60.5 x 59.5" Weight: 1700 lbs
Might Mite M422A1 WB= 71" Size: 113 x 60.5 x 59.5" Weight: 1780 lbs
Willy's Bobcat WB= 80" Size: 100 x 60 x 65.5" Weight: 1475 lbs
Haflinger 700 WB= 59" Size: 111.5 x 54 x 68.5" Weight: 1397 lbs
Haflinger 703 WB= 71" Size: 123.5 x 54 x 68.5" Weight: 1496 lbs
WB = Wheel Base