Yes, they are hard to find. We have Ollie's Outlet, where I find them. I try to get just a cheap queen fitted sheet for putting on my dogs bed, a queen camper mattress on the floor. The only trouble with getting the flat sheets is that they are usually of an inferior quality and shrink a lot. I guess for quilt backing that would work fine. For the dogs I don't care because they rip them up after a while anyway. I am always mending them.