Don't know where you are located, but suggest you talk to Mike at www.everythingledharleydavidson.com/about He supplies LED for all sorts of applications, not just motorcycles. He is going to set me up for ones on my 68 Mustang and possibly for the Bradley. Depends on the size of the headlight bucket if they will work on the Bradley. But he has them for turn signals, interior/dome lights, backup lights, etc.
I just met him last week at So-Cal Arizona in Phoenix.
Going to led shouldn't be a problem, they make replacement bulbs for most vintage sockets. They pull alot less than a standard bulb so the original harness should be fine. The only issue you might have is the flasher relay, they are activated by heat normally and the lighter draw makes them flash slow or not at all so you just need to replace the relay with one designed for led lights.