Had this tweet saved from last week, DigitalDesign passed along that he created two wallpapers based on The Sims 3 Showtime.  You can download them below on his Flickr page.  They are of 1024×640 size, so you may have to play around with the wallpaper settings to tweak it to your liking.

2 Sims 3 Showtime wallpapers from DigitalDesign http://farm8.staticflickr.com/7022/6587430101_f352291ef2_m.jpg