Putting the cab on wheels in general sounds like a recipe for a painful death, hehe. Locking casters would probably have you covered, but it might be unnecessary. You just want to be able to move them around the room?
When I got my 4-slot big red, I put it on some really nice furniture glides I bought from a nearby store. It's nearly impossible to make it move by accident, but once you overcome the amount of force necessary to displace it, it glides along effortlessly. Mine are made out a metal disc with a lip around the edge, and a big fat pad of low-friction plastic, like HDPE or something, for it to slide on.
Granted, I have hardwood floors. Though they're supposed to work on carpet, too.
Some things to consider with the casters though: Firstly, it will change the height of the controls. And secondly, the weight of the cabinet will be distributed over a much smaller surface (The area of the wheels actually in contact with the floor) so it might leave dents in the flooring. Using the original leg levelers on 2-3" diameter furniture glides gives a lot more surface area, and they are typically meant to protect the floor as well as make things easier to move.