Since the requests have increased.... a lot... let's get the rules straight so that it saves people from a lot of trouble.
1) States exactly what you want. This includes (but not limited to): the name of the anime/manga, the name of the character(s), the type of wallpaper style (tech, grunge, etc), the wallpaper size (1024x768, etc), the color (dark, light, purple, etc), focal point (left/mac, right/win)
2) include an image you'd like used on the wallpaper. Please don't say you dont know where to look because there is a HUGE sticky thread full of links to incredible image galleries with large scan images. If the wallpaper-er is going through all the work of making you a wallpaper (yes, good wallpapers take A LOT of time), the least you can do is find them an image or two.
3) be nice. No one is going to do a wallpaper with someone saying something like "make me a wallpaper of my bishie-boy NOW!". Please and thank yous can get you lots.