I recently helped Dawn from Dinkydoodle Designs create a cake for the 150 anniversary of the Nottingham Theatre Royal. The cake was presented to Prince Edward as part of the celebrations and he had the honour of cutting it. The cake was built in 2 halves and 5 floors, each floor had a baseboard (laser cut), built up with sponge cake and covered with chocolate ganache before the decoration and detailing went on. The floors were separated with cake frame to stop them squashing the sponge (now available from Lakeland plastics apparently).
My involvement didn't stop with base boards though, once the basic shape was carved out I was called back in to wire the cake with lights. The front porch is lit, the chandelier and auditorium were illuminated with LED strips and the stage area was lit with a WS2811 strip and an arduino nano changed the colours every 10 seconds to give a sense of movement.
Here is a little video tour of the cake once it was opened.
The cake was built in 2 halves so that the internals were hidden until the cake was slid apart allowing people to see all the extra detail on the inside of the cake. Dawn has more photos of the cake on her facebook page here.