Eureka! Master bath walls are already green, and I committed to a white vanity when I let Spouse build white shelving over the toilet. Beige-ish countertop, dark wood floors (we'll use wood-look tile): DONE!
Home improvement stores like Home Depot can cut a large section of carpet of any size and have it finished for you. The end result looks like a designer rug but for half the price. Also, these types of rugs look great layered.