......by the way, Bert, I have to disagree with your initial assessment of the suitability of the BionX PL-350 for my application. I live in Portland, OR, which is well known for its hills. Two weekends ago, I was taking my 9-month-old son (picture below) into downtown Portland. He was in his car seat in his Burley bike trailer, attached to my BionX-powered Go-One. I found myself going up a 5% incline hill in downtown Portland. I didn't want to block traffic, so I hit the throttle on the Go-One and put the hammer down on the pedals.
It was like I had been shot out of a rocket! I cleared the high-traffic zone without slowing any drivers down, while pulling over 45 kilos behind my 40-kilo Go-One, powered by my 84-kilo 45-year-old self! I never even hit my max heart rate (something I did regularly when pulling the boy behind my road bike). That would not have been possible without the BionX. An acquaintance of mine, who happens to be a bike racer, saw me from two blocks away and tried to catch me, coming up the same hill. I was able to pull away from him on the Go-One, thanks to the BionX's capabilities.
Based on this experience, I think you can tell potential BionX customers that it can handle even substantial hills with aplomb!