Trek Lime has the same drivetrain, as well as a Schwinn version. I think they all were out around 2008-09 but they didn't catch on because they were expensive ($5-600). I tried to go look at a Trek for $125 2 weeks ago but couldn't hook up with the seller, then saw the Schwinn at a LBS for the same price. Was told the drivetrain is hard, if not impossible, to swap to a different bike. Nothing is impossible to Rat-Rodders, but I got busy and haven't revisited the idea.