OzJon, I have a bike rental and tour business in Yokohama about 30 km south of Tokyo. I only rent small folding bikes (and a couple minivelos) which are good for short rides in the city but if you are interested (and aren`t too big) I would be happy to rent you my own bike, a Dahon Curve SL. It`s really a great little folder definitely capable of longish rides - plus it folds quickly and compactly.

click the link below for photos and also -

www.yokohamaliving.blogspot.com