I was at the Geffrye Museum recently for a little visit with my son. They have lots of period rooms which I am a sucker for since I worked at the Brooklyn Museum where we had some great ones. The room that caught me on this visit was the 1890's drawing room. I was really struck by how unadventurous our interiors mostly are these days in comparison. We might use a bit of wallpaper here or there, but tend not to mix lots of patterns in one room any longer. In this small room there's so much going on but the overall sense is one of calm and balance. I've worked with lots of interior designers over the years but unfortunately many of them stick with pretty neutral palettes, it's certainly easier to design like that so I suppose that's why they do it! http://www.geffrye-museum.org.uk/period-rooms-and-gardens/explore-rooms/drawing-room-1890/
A designer who doesn't work this way is Frank de Biasi in NY. The apartment he shares with his partner, Gene Meyer uses lots of patterns and layers in terms of books, art and objects that they've collected. http://www.frankdebiasi.com/projects/manhattan_brownstone/
I also like some of the work of Wary Meyers, in their interiors they love a bit of wallpaper or stencilling which gives their rooms lots of personality like Frank de Biasi's. http://www.warymeyers.com/Resources/viewin.jpg or http://www.warymeyers.com/Resources/guestroom2.jpg
There's a good exhibition on at the V&A about the Aesthetic Movement right now. I'm not a fan of that period or style of painting but the decorative arts of that movement are great also how they changed the way people thought about their interiors.