Best bet is going to be building your own insides for vintage cases. I have several vintage lights, including a couple of NOS and they are no match for today's stuff. Biggest problem I have with my vintage lights is the reflectors are usually pretty rough, which doesn't do much for beam pattern. I have used the
B&M Retro on one bike as a compromise, it looks vintage but gives me better light than any of my vintage lights. Spanninga makes one called the
RetroLed, it is nice looking but is marginal when used as a stand alone light.
Aaron