I have found over time that essentially all shop items that I build need to be on levelers or wheels. My old main 44 year old bench is not on levelers or wheels, but that is the only wood on concrete structure I have. All others are on some sort of levelers….....as a minimum, carriage bolts. The other exception, which doesn't count since I didn't build it, is the repurposed scroll saw stand that holds my drill press.
In the last few years I am taking an additional step. I am using torsion boxes liberally in most items. My multipurpose bench has the two end piers built as torsion boxes, but the base isn't. If I were to build it now, I would make the base a torsion box as well…...all I would need to do is put plywood on the bottom, since the bracing is already there. But it is built so heavily, that it doesn't need it. The torsion boxes actually allow your structure to be lighter.
The torsion boxes allow you to place solid corner pieces inside the torsion box to hold wheels or levelers. My cutoff cart is a scrap wood torsion box with wheels, with some modular compartments on top that can be picked up and carried to the work place. The outfeed table I am building as part of the dust control for my TS, will have a torsion box on the top and the bottom. At La Conner, I have a bench composed of two torsion boxes that are placed on pedestals. The pedestals do not incorporate torsion boxes because they have to nest for storage. But they are quite strong, and will have levelers as well. The stationary bench in La Conner is a cheap solid core door that was purchased for a quick and dirty work surface to help build the rest of the shop. It has a plywood top cover, and the door with its cover will become the top of a torsion box. Currently it sits on saw horses, but I will build pedestals that have a torsion box on the bottom, and the top will be kind of built into the top torsion box.
If you are going to beef up those cabinets, think about the height carefully. You might be better off with the whole thing higher, and the top and bottom could be built into shallow torsion boxes, the bottom incorporating solid corner pieces for wheels or levelers….....
If your shop stuff is designed to all the same height, make them all taller and stronger, and in the process make it easier on your back…........
You can use some scrap and cheap stuff to make the torsion boxes, just use a lot of glue and a nail gun…..