This is a simple svg wallpaper I did. There is a problem however---it seems that KDE can't handle radial gradients so this design doesn't quite work. I thought about submitting this as a KDE4 brainstorm so as to draw attention to the need for this ability. Konqueror displays radials just fine, so it doesn't seem like it would be complicated to use the same code to display a wallpaper. In the meantime, either export this as a bitmap or change all the gradients to linear and adjust it to your liking.