I have a Winchester Model 12 in a glass-fronted wooden display case on my wall.
My father made the case. The gun was my grandfather's, who died long before I was born. The gun later passed to my father's older brother, who also died before before my birth. At some point, the gun passed from my father's brother to him. My father gave it to me in 1998. He had a brass plaque engraved that has the names of the previous owner's and the dates of ownership. The original date is 1936. I put a couple boxes of old paper shotshells in the case for visual effect.
My father picked up woodworking as a hobby some time ago, and has really progressed. The case is beautiful. I wish a had better photo pasting skills.
Edit: Oh, and the gun is operable. I've fired it many times. Sometimes the pump action sticks, but only after firing. It never sticks when it's cycled manually. Weird.
I did add two small clasps with tiny brass padlocks to the case door to keep honest people out.
According to my Dad, my grandfather used to partake in live pigeon shoots with the gun. Apparently, this was a pretty big deal in Pennsylvania at the time, with lots of money being wagered. My father says his dad was very skilled at it. The gun also has a custom fitted stock, made for my grandfather to compensate for some arm injury he had sustained.