Back on Jan 29th I was at the train show in West Springfield , MA and saw an interesting module at a large HO scale modular club. This is a night time city scene with emergency vehicles at a building fire. The video does not do this module justice but may give you some inspiration for a night time scene. This was done by an individual who bought the parts and put it all together. You would have to do some searching for the vehicles and LED lighting parts. There may be kits for some of the items.
http://www.youtube.com/watch?v=iPerHGFalVE
Rich
I was surprised to see how effective the black "tent" over the module was in creating darkness for the night scene. Once in a while I have seen a night scene on a home layout tour but that is the first I have seen designed for a train show. Thanks for posting the link.
Jim