Hey, thanks for the compliments you guys - I love this bike. Answers to the questions posted above:
Corgi1, you asked about sourcing the Shimano rollerbrake - I did a quick Google search and found the BR-IM70-R for only $35 (probably a short-term sale) at this website: Shimano Nexus/Nexave-M70 Deluxe Roller Brake Kit - Outside Outfitters
. Dangit, that's about $30 cheaper than I bought mine for
Mabman, my initial intent was to use a rear disc-brake adapter (like this one: Disc Brake Bracket Billet - Choppers U.S., LLC
). So I ordered one, and when it arrived I realized that the way it works is to transfer all the torque from your braking effort into your left-side rear dropout. My dropouts were already looking pretty chewed-up to begin with, and I'm almost positive that the left one would just bend out completely if I tried to use that adapter. Those things would probably work well if you have a nicer frame with stronger dropouts, like a Felt. But so far, I'm still really impressed with that rollerbrake.
Svc, the range of gear ratios on the Nuvinci is best visualized here: http://www.fallbrooktech.com/Docs/Ge..._011309Web.pdf
. In practice, I can accelerate from a stop without pedalling, and with a basically unmodified engine, I top out on flat ground at somewhere between 32 and 35 mph (according to my speedometer). There's still plenty of gear-range above what my engine can push currently - if I get brave and attempt some porting/polishing soon then I suspect I could get it faster.