Doubt you'll find any OEM bikes from the "majors" (Trek, Specialized, Giant etc) that can achieve speeds in excess of 28 mph since this is the "Class" maximum, and these IMO would be the most reliable, although I would eschew anything with Brose or Shimano motors since I've read about more problems with those than with others like Bosch and Yamaha. If you want to go faster, look at Bafang. I've had good service from my DIY systems with their motors.