I had a thought about motor mounts. Most everyone seems to use clamps of some kind, and even really nice clamps aren't very elegant (sorry, no offense intended). I worked at a bike shop for about a hundred years around a thousand years ago. We had a tool for adding extra water-bottle cage mounts to an existing frame. It worked like a pop-rivet tool. You drilled a hole, inserted the "pop rivet" and the tool compressed it into the hole. A nicely reinforced threaded hole was left behind. Just for giggles, we put one on a wrecked frame and tried to remove it by screwing a bolt half-way in and applying a crow-bar. We destroyed what was left of the seat tube, but it never came out. You wouldn't want to do this on a high-dollar thin-walled steel bike, but we did it on a number of run-of-the mill mountain bikes and never had any problems. I believe Cannondale bikes use a similar method for their stock locations. If these tools are still around, bolted-in motor mounts (maybe with rubber bushings) might be fairly easy and could look really slick. Just a thought.