What I do have is a number of paper drums and a rotary base. The rotary base offers continuous rotation and reversing rotation. Just nosing around, I found that my plastic film tanks fit perfectly inside them.
Many people use the paper drums to process sheet films. If you have Paterson tanks, just load them up and toss them on the rotary base. It works very well. For the tank that holds 2 120 reels, you may need to add a heavy block (like a brick) on one side to keep the tank from falling off. It's pretty obvious once you start doing it which side it needs to be on.