I made some wallpapers that correspond to the 16 default track colours in Cubase SX 3. There are two variations; one is plain, the other has a subtle pattern.
You will need to copy the files to your wallpaper directory e.g. C:\Program Files\Native Instruments\Kontakt 2\presets\wallpaper
I also included two multis to load each of the wallpaper variations, so that you can see all of the colours.