If you can get hold of a Walthers catalogue, Faller, Kibri and Preiser all feature a large amount of both American and German WWII military equipment. I wouldn’t be surprised if you can find a WWII staff car in the catalogue. And if worse comes to worse, check out the “Vehicles” section of the catalogue, there should possibly be a 1940’s 4-door sedan that could be adapted with a little olive-drab paint and some decals.
Minimetals has a nice '34 or '36 Ford out - paint it Olive Drab, put a white star on the front doors - you have one - the Army was never one to have only the newest equipment - the '30somethings probably lasted into the '50’s!![:)]
The Mini Metals 1936 Ford you refer to now comes in a dark sand color which would look really cool with a white star on the doors, red flag with gold stars, as a generals staff car. I had one in my hand today, but you cant buy everything you want, all the time.
I happen to own one, 12 to the foot of course. Mine is by Dodge, 1942 M2 Scout/command, all wheel drive, makes a Hummer shudder with shame!! The armour plating is missing on mine, good thing considering it gets about 6 mpg in a stiff tail wind. Don’t know if there is something you could rework out there, think early SUV with very large fenders…