Sweet build you got going there. Man, I envy you three things: shop space, welding skills, and obviously a good assortment of tools. That is one very creative bit of engineering you've done.
I been wanting to build a tadpole leaner for a goodly while now, and have thought about doing something like the Honda gyro rear wheel pair and engine mounted above it - the pocket bike engine/cvt set-up would work pretty well for that. Really it would be a four wheeler, but set up so the rear wheels are less than their own width apart witjh the drive sprocket between them, in a common suspension able to twist on the axis of the bike frame front to back - front wheels lean, rear end stays normal to the pavement.