Chris has a lot more layouts than you, just ask him for hints on how to stack them.

I've been trying to convince him to sell one for a long time...
The diorama idea is neat, just so you have a memory of the layout. Like Lance's Monon layout... it's really hard to archive someone's home layout. So, I'll hang onto this diorama as a tribute to a great layout:

I don't collect much in the way of special runs, etc, but I do like to collect examples of good modeling from good modelers. I picked up a few gondolas from the fire sale at N Scale Supply to display on here as well.