There's a growing group of homebuilders who are converting vehicles of all sorts to electric power, motorcycles among them. This motorcycle is a Derbi GPR 50 where the builder removed the original drivetrain and installed 6 lead acid batteries, an electric motor and a DC converter.
The video is a short walk around of the bike and then a ride around the neighborhood. The performance looks very acceptable and is reported to be 0-60 in 9 seconds with a top speed of 75mph.
The problem with electric motorcycles and any electric vehicle right now seems to be range which is a trade off with performance, more range less performance and vice versa. The alternative is to use a lot of very pricey Lithium Ion batteries like the recently unveiled Tesla Roadster or a hydrogen fuel cell where hydrogen fillups are a bit of an issue. In any case, things get expensive very quickly unless the ENV fuel cell motorcycle does come in around the $6000 mark as the company claims is their target price.
There are some very impressive racebikes built around electric power and scooters like the Vectrix available for sale
I like the home builder attitude and the results are encouraging but I think we still need battery technology to advance a bit or hydrogen filling stations in more places before we'll see very many electric bikes in every day commuter use except for very short range purposes.
Electric motors do have some amazing performance possibilities with extremely high torque available from a dead stop so you can bet more and more of these bikes will pop up. Interesting.
Got this tip from two readers almost simultaneously, Thanks, Jeff and Drew!
You might also want to check out ElectricMotorcycles.net