Do you have any ideas on how to position the lights under the backlit displays? I always used well-placed duct tape, but it never really worked well. I've also head of people using chicken wire or screen door mesh as kind of an under lattice-work to attach the lights to under the plexiglass display.
I'm actually going to use these little lights that will be attached by drill through the hardyboard, insert them, put a dollop of hot glue on them to hold them in place, then secure the overlay to outside of the hardyboard. We're still undecided about whether or not to cover the outside of the overlay with plexiglas or acrylic or just let it ride.