I've been experimenting with GIMP, trying out a few light and texture effects, and came up with a couple of large Matt/Becker graphics. I know they're both entirely the wrong size and shape to be wallpapers, but if anyone wants to snag them they're both free to a good home.
Also, if the first one looks familiar, it's because it's the large version of an icon I posted recently. Most of the effects were, unfortunately, lost when it was scaled down to icon size, so I've posted the full size version here, because it works much better than the icon, I think.
Link to the full size verion (801 x 801)
Link to the full size version (879 x 1000)