I never could get past craving a set of 59 Caddy lights, so I had my son whittle up some brackets that mimic the fender shape.
I seriously considered 50 Pontiac taillights mounted directly to the fenders, but the new reproductions didn’t exist at the time, and decent originals were both expensive and difficult to find. I’ve seen several trucks with late 50’s Corvette taillight scoops added to the sides of the fenders, with either stock Corvette lights or Caddy lenses added. It requires a lot of work and I don’t care for the finished look all that much.
On a low budget build I like the idea of the frenched fleetside lights. Also check out the Lakeroadster build thread. I think he installed Impala lights on his and they look great. Once the base is in place, I imagine you might be able to play around with different lenses for even more variation.