Inexpensive craft store frames fit perfectly around light switch covers! --I like the LOOK Expensive (but not really BE expensive! -- 31 Easy DIY Upgrades That Will Make Your Home Look More Expensive--
styrofoam covered with fabric wall art. My daughter and I did this for her room. We used cheap painter canvas and scrapbook paper. We sprayed adhesive glue to the canvas and layed the scrapbook paper on top.