Maybe you can pre-emptivly strike against re-decorating her room like a walk-in closet by enabling her to wallpaper her room in posters. Go crazy- add 2-3 posters for every wall. It could be a temporary, yet delightfully tacky look you could compromise and both agree on, giving her the satisfaction of an interesting and busy visual and confining it to a two-dimensional plane that might save your sanity. Plus it's an excuse for the two of you to go shopping! Don't forget those little plastic things that go on the posters.
I'll always remember the year my mom let me paint a mural on my bedroom wall. I copied an Indian princess viewing her wedding dress in a river from a magazine advertisement selling a decorative plate. We were renting so I had to repaint the wall white when we moved. Ouch! It was worth it!
