A good friend of mine just returned from spending 3 weeks in Italy. His friend lives in a 45 (!) bedroom villa, by himself. Needless to say, he doesn't use all the space he has. The room he does use a lot is the living/dining room. As soon as I saw the pictures, I said, "Look, he has slipcovers!"
I can't tell for sure, but the fabric looks an awful lot like a light blue denim. Even with fresco-painted walls and 20' ceilings, slipcovers are appropriate. I just love it.