Stubby tank car?

I really like my Kickapoo Valley 4 wheel side dump cars and cabooses. The gondolas are much less my favorite. What’s missing in this world of cute 4 wheel Lionel cars are tank cars. Does anyone know of any short, wide and roundish tanks that I could use to make 4 wheel tank cars from? I saw at Menards some kiddy starter sets with pastel colors made with some of the Kickapoo Valley cars from the 70s.

I don’t know how big the Kickapoo frames are, so here are my best guesses.

The Marx 6" tank car is common as dirt, especially in the Santa Fe name. Make sure if you go with this car that both end “caps” are there. They also made this car with two different ends one is noticably more domed than the other.

If that tank is too small, perhaps the Lionel prewar 654 might be better suited. I couldn’t find a picture of one in my library, but they are also pretty common.

If neither of those work for you, perhaps you can buy some PVC pipe and some end caps, and make your own. If you go this road, I know I would like to see what you come up with.

J White