Slightly different makes/models, which I guess would have served the same purposes as your truck; might give you a few ideas. The 1939 Chev "sally bash" version (2nd photo) looks interesting.
There's a few panel vans of varying types on this site, mixed in with some nice CMP pictures:
http://silverhawkauthor.com/mobile-s...-rcaf_481.html
In the 'standard military motor vehicles' data book, the later 1/2 ton dodge panel truck is identified as "to transport light cargo"..
Nice project!
Owen.