There are so few options for wallpaper. I've searched and can't find how to make and submit one. Can someone fill me in or link me? I'm a graphic designer, I should be able to make some more acceptable wallpapers for the community.
I don't think it's possible. At one time Roku was going to inform developers how to create themes (as they're called), but that never transpired. It could be that I just missed it since it wasn't something that interested me, but you can try to search for Roku theme development and see if you get anywhere.