Here is a treadmill made for serious runners. The 3G Cardio Elite Runner Treadmill has a commercial grade construction with a 4HP motor. It has 400lb user capacity. It has a 22 x 62-inch running platform. Its speed can accelerate from 0 to 12mph in just 18 seconds.
This treadmill has elevation settings up to 15%. It comes with heart tracking with a wireless strap. The 3G Cardio Elite Runner has built-in speakers. You can find out more about it here.