I have seen pictures of a truck that had an electric step that operated like the Class A motorhomes. It was a single step. Do not know the source or name.
I installed running boards on my F350 dually and there are extra mounting holes under the truck that one could fashion hangers to add a single stationary step that was lower than the running board if they desired. Or weld extensions to the factory brackets to extend down for another lower step. I fabricate step hangers for steps behind my running boards that I used to mount a single step to be able to stand on and access my bed tool box.
Just takes a ;little engineering and fabrication and it is very possible.