I didn't know what a banjo cooker was...Wow, holds a 100 quart stockpot..Now, I want one.and they're not that expensive, either.
Had to search banjo cooker, had never heard that term. We have made them before using the burner from a gas stove, but they can be made from a coil of copper tubing with jet holes drilled in it if you like to build stuff. We used them to cook seafood outdoors or deep fry turkeys.