Here is a rar of a PSD file, and a few pre-made "skin" files for the 800x480 resolution.
Just take the 2 picture files and replace the two in the "background" folder of your "800x480" skin folder.
You can use the PSD file (in photoshop) to make a skin file with the background of your choice. Just replace the white background with whatever you want. bring the "UP" buttons to the top, and save it is your backgroundup.jpg file. Then bring the "down" buttons to the top and save it as your backgrounddown.jpg file. I also included two layers of brightness control, that will give that rounded edges look to the playlist/DIR boxes.
Here is a preview of my drkblue/grey combo: