There was also a company that contracted with Ford back in the 40's and 50's to make a crewcab for fire fighters, and rail roads. Look at the old Ford borchures from the 50's. One of the options they show are a crewcab.
Reminds me of a story my dad told about when they first came out with flashers and electric turn signals - they were dealer add-ons. The salesman had sold this woman a new car but she refused the turn signal add-on.
When he asked her why, she answered "Silly, only a fool would beleive that the car behind you can hear the click when you turn them on!
RailRoad special ordered them for years - I have seen a 1948 or thereabout crew cab. Even the old Model A's and original T's had a 6 man cab for the fire trucks.
There was a 56 drew cab (3 door) railroad special featured in truckin magazine about ten years gago. They were not done by ford, but order through ford and done by a private company. Much like the marman herringto (sp?) 4 wheel drives were back then.