The lovely folks over at The Fox is Black have been releasing a treasure trove of awesome desktop designs as a part of the Desktop Wallpaper Project. I found the webpage to be a little slow to load and there is unfortunately no way to download all backgrounds as a bundle. I wrote this little script to grab all the background in 1400x900.
You can find gleitz's entire dump at this link.
I added some features I missed: Downloading only new wallpapers, in a single session, and stopping upon reaching an empty page. Also added some prettier prints.