as to a generator motor combo, they do and have made them. well, not a generator, but an alternator i guess. some of the old generators and some of these pocket bikes (gas fired) have a combo starter (motor)/alternator. granted they do not work at the same time, but if you were to use 2 sets of coils instead of one, you just might get both at once out of the same unit. theoretically, if you can find out what trips the starter/alt between it's functions; say it is normally an alternator, but pushing the starter button makes it a motor, well you could hack the button and install the throttle. provided of course it would handle being used as a motor vs a starting motor. if dynamo A puts out x juice, how many dyanmoes will it take to make R the required juice? they could be arranged so that they look like a fender, or a planetary system. i also have heard of some circuitry that will boost power, it could be installed between the dynamo and battery bank. i don't recall if there are adverse effects with this simple power amp, but it may be worth a look.