You could probably do the HID off the dynamo, IF you were willing to lug around the extra electronics and a battery pack to make it work. They battery could charge when you're riding during the daytime, then run the HID off the battery at night.
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"There is no greater wonder than the way the face and character of a woman fit so perfectly in a man's mind, and stay there, and he could never tell you why. It just seems it was the thing he most wanted." Robert Louis Stevenson
