Was out at my friends dealership today and seen they had an electric mountain bike. Its a SSR srx250e e-xtreme. They let me ride it around the shopping center and I have to say I'm impressed.
That's often the problem with e-bikes, people are intimidated because all the costs are up front, followed by 1000s of miles where maintenance and operating costs are next to nothing. Best bet is still to put a kit on a bike you already like.