Farmhouse Dreamy Interiors
Green trellis wallpaper in Chloe Sevigny's apartment.
Tory Burch in The Hamptons Living Room via Vogue
Creating a New Old House - Garden Interior Design - House Beautiful
Forget wallpaper. If you have a college nearby with a decent theater program, they should some have students in a scene shop who can do this, too, for a decent price or class credit. Ask for the students' portfolios before hiring and a reference from a theater teacher. Remember, not all artists are created equal. Someone in theater will have experience in faux finishing, working on large scale projects, and recreating from pictures.