I was asked by Glaedr if I knew of any tutorials on how to make this sort of wallpaper, but I didn't. I noticed other people post tutorials, so I thought I would too. You need the gimp and Inkscape for this. And it DOES have to do with gnome ;) Why else would you want it? The screen shots here show the main steps included in the tutorial, to give you a feel for how difficult it will be.
If you make something with this I would love to see it :)