Have you looked at www.cleverchimp.com ? The Stokemonkey links electric power directly into the drivetrain of the bicycle which allows the motor to operate at a more efficient rpm. These are designed to run with an Xtracycle equipped bike. The whole rig would be higher priced than the bike I saw on your site. Also, Todd Fahrner writes a pretty entertaining blog which is a good place to keep up on bike transportation. An option worth considering would be the Fraser Cycles Frontier with the Stokemonkey. It may not fit your commute if you include the train.