Thanks for all the suggestions. Those card stock models look too futuristic for what I had in mind, I'm really looking for something in plastic, resin, or metal that would fit easily into the 20s and 30s era. I'm building a refuelling truck for my rocket corps troops...
After some research online I think I'm going to go with something like the Sloppy Jalopy Ford AA flatbed and then kit bash the reservoir tank on the back from my bitz box. Would still be interested in hearing of any other sources or see pics of any fuel trucks people have in their fleets. I'll post pics of mine when I get it done.
Cheers,
A.