re: Plywood Storage Rollers

That is very similar to what I use. My storage is just a few rails from 3/4" galvanized pipe. I can see how dividing up the rails into individual wheels may make it easier, but with my setup, the plywood slides easily, it is contact/sliding against neighboring sheets that really adds the friction.
Seems like a lot of work for minimal benefit.
You could even just place some melamine on the floor below the cage and get a nice surface for sliding.