Awesome job, I can almost hear my missus in the background asking why on earth would you do that? To which the obvious reply would be "'Cos I can". To be critical, the drive system needs some "smoothing", not saying I know how, but I think it could be worthy of more research.
OK - actually watched to the end - take the "kink" out does work, would still like to see a smooth version on 2 levels though