Im pretty sure you can get a vidmar cabinet close to 3000 lbs if you load every drawer with steel offcuts or the like.
That means a 750# caster...
Which is around a 5-6" caster. Swivel is going to be 6-7" from the base to the mounting plate.
Pretty tall for a 59" cabinet.
The danger is that you send the 3000# crashing onto you, or even half of it and your life is going to change in a big way. Not worth the potential in my book as I pack them like a rat.

I crashed a Craftsman base once when I was rolling it and a caster stoppped on something like a pea gravel or a nut which caused the sheetmetal attaching screws to pull out. It didn't balance well on 3 casters and crashed dramatically, destroying a couple of drawer slides. That's the first and last one I want to tip!
My solution is to build a base from 2x4s on edge and 3/4 plywood deck, deck screw. Then I can easily use a pallet jack or forklift to relocate them. Only need 1/2" lift off the ground to move it if the concrete is smooth, use forklift if its any rougher. Have not been able to crush a 2x4 with them yet
