Vic Eaton sent me pictures recently of a C15 in the North African desert.
Although it's resolution is not great, you can see a frame fitted to the side of the canopy and rolls of canvas on top:
I recalled seeing this frame on 15-cwt truck before, and today I happened to come across a picture depicting the use of this frame.
It looks it was used to attach an office tent to the (possibly both) side(s) of the truck:
Caption: A CMP Chevrolet truck in use by AFPU cameramen in the Western Desert, 28 April 1942
Question: Does anyone know more about this variant?
Thanks,
Hanno