More: it sounds as if this is a stage prop/scenery. There are special considerations for making props. For example, if you want to make a convincing stage dagger you just need a stick that is shiny, rather than careful workmanship.
Wallpaper to be viewed from no closer than 12 feet can be a very crude design indeed. I just spoke to someone who knows something a about stage props: she made an excellent point. Whether you print it yourself or have it printed, the cost and effort will be orders of magnitude higher than - buying cheap wallpaper. It's easy to lose track of these and take time away from making more interesting parts of the set and scene.