Here. I get them from Banggood in China.http://www.banggood.com/5_75inch-60...ycle-Headlight-For-Harley-p-1027814.html
The bike was already equipped with the three pronged plug for sealed beam. Case is floating so the light can be hooked up to positive or negative ground. It is primarily intended for daytime lights on running, not night riding except for occasional use as there is only one beam in use.
Not remotely vintage looking, but vintage look available with a little searching using the bulb type with reflector.
Hope that helps.
PS Try searching Liliha's Bakery in Honolulu, or send them a message via email email@example.com