Sometimes, technology is a wunnerful thang (when it's not being a giant pain in the ass...)
I needed a milk hauler for my diorama. I started out with this:

a 1/64th scale Ertl tractor. K-whopper I think, can't tell for sure.

I popped off the 5th wheel and cut a tank out of some 1/2" PVC pipe.

added some domes from my junk box

and some skirting from sheet plastic and popped it on the truck.

The crowning touch was a coat of silver metallic and some MMPA (Michigan Milk Producer's Association) decals I swiped off the innerwebs, resized and printed on wet transfer decal paper on my new Brother LED printer.