Originally Posted by BlazingPedals

Unless you're willing to go recumbent, or at least semi-recumbent, using 20" wheels won't put you any closer to the pavement. The bottom of your pedal circle still needs to be the same distance above the ground so you don't have pedal strike every time you turn the wheel; and you need the same amount of knee bend at the bottom of the stroke. Some folders/mini-velos have a lower step-over height; but again they don't have a monopoly on that feature.

Stepping over my lowracer, with its 8" seat height, is obviously a non-issue. Getting settled down that low is a multi-step process though.