does anybody make a 12 volt hub dynamo? i read somewhere that there was to be a 12 volt version of the schmidt unit, but heard no more about that in a while. also, does anybody use the b&m s12 bottle dynamo? any comments about it's brightness? drag? just curious. p.s. i know you can get 12 volts from a 6 volt model by wiring 2 lamps in series & pedaling your but off, but i'm referring to an actual 12 volt version....