I had considered doing something similar to what
dazzasgotav8 (Darryl?) has done above, soldering tails onto the contacts of the bulb holders, but then soldering the other ends to the appropriate metal back-plane locations.
The only concern I had was around the ease of changing lamps - it could get messy with wires (tails) everywhere.
dazzasgotav8's solution above deals to that nicely!
