Awhile ago I ran across an interesting video about a factory that produces architectural models, among them skyscrapers: Strange Parts. Pertinent to this thread is the segment running from 21:42 to 25:30 demonstrating how they light their buildings, with wire "power rails" tacked to the ceilings using hot glue, and surface-mount LEDs soldered across the rails anywhere a light fixture is needed. The wires are gathered together in the core of the building and run to the base, where they're connected to a control box.
---PCJ