Well, not if you wanted to be able to edit what the back looked like. If you just wanted to set it as a pre-set image, then it'd be easy, but that wouldn't be well-built...
Actually, now that I think about it, I could do that, but it would take a metric ton of code, and it would only be usable by those who use Ander's template. Making a whole new template would be easier and accessible to a much wider audience, and templates don't take up a whole lot of space - they're just some images and text documents.