I'm working on my first from-scratch theme right now, based on an awesome wallpaper I had floating around (unfortunately, I can't find the artist to ask permission, eek). It's going to be a single-box theme, like SerialX, but with stuff in the background that looks like it's part of the wallpaper (thanks gogg, for the idea). Unfortunately, I've got zero artistic talent to do the wallpaper any justice in the lsbox and the popup.
Here's a screenshot of the theme as it is now (heh, ignore the serialx stuff, it's placeholder material. http://members.lycos.co.uk/lardboard/screen4.jpg