[DaveL]

That is an interesting design. I would be interested in it, if 1 wheel can support 100 pounds, as having one smooth rolling wheel would likely save space and weight.

Is this out on the market or a design idea?

If I were going to build this, I would give the shorter roller twice the diameter so there is room for the axle. This roller could also have a bow-tie look from the side to reduce the gap with the longer roller.
D