I fully agree - Scrapped Princess is a great series! :)
And onto the wallpaper critique: I like how you've taken one color to focus on for the background and used different hues. It makes the characters stand out. At first glance I thought the castle was being viewed through a window, but then I saw you'd broken it up into blocks, and I like this concept. It adds more tension. The extraction of the characters is a little on the choppy side - especially when I look at Shanon's hair and down on the lower right side under the "Madman" title, it's really choppy there. By smoothing out the edges I think that this would allow you to eliminate the back-light/glow around the characters. You might want to think about using the heal brush (if you're using Photoshop) to color over the technical copyright stuff that came on the original scan (as I'm assuming it did). I'm not good at vectoring myself, but I find that this is an easy way to clean up text sometimes. :) You've got a good concept and have put the wall together nicely. Keep up the good work! And put your name on stuff! ;) That way people will know it's your work and you're darn proud of it! :) I hope to see more. :)