I own a fat tire heavy Mtn. bike that runs a BBSHD. I love it, as it has a throttle. I'm 70 YEARS old and need a throttle. I now have difficulty getting my leg over to mount my monster. I am looking for a step thru bike with a BBSHD or other powerful mid drive with a throttle. Am I going to have to build one. Stunner is fair and my wife has one but is is a BBS02, which I will probably burn up. Any conversion frame suggestions or a factory built option. Requirements area large reliable mid-drive motor, throttle, Step thru frame. IGH would be a plus.