Hmm...let's see.
Back in the '80s, when I was heavily into HO, I considered (3) different projects, none of which I followed through on:
1. A large scale circus scene
2. A Disneyland-type display
3. Since I was born in Waterbury CT, I thought it might be cool to do a scene of the heavily industrialized downtown area. I picked my Dad's brain and was able to come up with a diagram of what he remembered. Seems there was a big roundhouse, etc in the mix; having the internet back then would have been a big help! Nothing ever came of it, though...
Mark in Oregon