I'm diggin this...

...Panasonic's Vivi RX 10-S, which is due in Japan on August 20, works the same way many hybrid vehicle systems do: taking the energy from braking and harness it into recharging the battery. The total assisted travel range combining pedal power, electric power and electric regeneration is around 55 to 77 miles ...

 http://gizmodo.com/5022587/panasonic-makes-electric-bike-with-regenerative-braking