Originally Posted by twowheeledfox
That's a good idea- only problem is that if it sprung back too easily the motor might accidentally be engaged while riding pedal-powered. I was thinking an old lever for a front derailer mounted like either a sideways shifter, or a suicide lever on the steering stem. Of course, the lever would probably not stay in position when the clutch was engaged.
Yea it would have to be a hard lock like the clutch levers have. That's why the second best way would be controlled by something your hand is on 100% of the time, like the grip.
Also a click-shifter might work. But it would have to move a heck of a lot between gears. I believe you can get the left-side ones for 2 gears (front derailer) for 2-speed cranks.
The only other think I could think of would be the lever shifters for the older 10-speed bikes that stick right on the handlebar stem. They have plastic adjustment wingnut but if you replace it with a hard hex nut you could tighten it quite a bit (plus lockwashers, perhaps double-nut it, etc to keep it tight). Then just weld or bolt a longer piece of metal to it to get more leverage for an easier pull.