I had thought about a large D9P for mine, but never did. I tend to do mine in various width strips or extra blocks, depending on what I have for leftovers. Here are some ideas for quilt backs..I started this post a few years ago. One of these days I should update it. I'm sure I've got several more pics I could add.
http://www.quiltingboard.com/picture...s-t148395.html
Also, there is a a free Craftsy class called Creative Quilt Backs that might be a good resource for you. I usually sketch mine out or play around in PowerPoint to get an idea of what I can do with my fabrics.