Here's a detail of the wallpaper we're using. It's from the 50's. We got it from a place that most people know about called Second Hand Rose which is at 230 5th Ave on the 5th Floor. They have some great stuff. Sadly, after being in business and digging in hardware store sub-basements for 50 years, they are going to be closing soon. Props to my friend Martin who's worked there for 41 years, who helped me figure everything out, and taught me how to keep old wallpaper moist. Basically, his advice is to bring it into the bathroom when you shower, so it gets a little steam on it. That way, it won't crisp up.
Below is the wallpaper that my wife and I have in our bedroom. It's from the early 1900's and it's not really like wallpaper at all, it's more like newsprint. 
When my wallpaper guy Cliff (the greatest wallpaper hanger in the tri-state area) started working with it even the great one balked. He called me and said in his Staten Island accent, "It's like terlet paper. It's falling apart in my hands." But in the end, he did a top rate super-excellent job.
Here's the set with the right wall covered in the polkadots:
And here's the other option with the polkadots on the main door/wall fabrication:
And just to prove that the little staircase is real, here's my set-builder, Jacques, building it as we speak. He's not the best guy at schedules, but he works wonders with wood. Jacques is from Texas and is a big fan of that show American Pickers. He plays guitar and has a killer recipe for Chicken Marengo.
