Surly does a different color theme every year or so. Since they are a smaller company, they tend to have each bike in only one or two colors each year.
If you order your Big Dummy through Xtracycle, you can choose any custom color for $250 more. (Surly and Xtracycle worked together to create Big Dummy, and Aaron Goss was one of their testers!)
For a while, to publicize the paint options, Xtracycle offered framesets in 6 or 7 different colors at no extra charge. I was THIS close to buying a frame set and hiding it under my bed until I could build it up. There was this lovely pale green...
http://www.rideyourbike.com/
http://www.xtracycle.com/
"If Americans want to live the American Dream, they should go to Denmark." - Richard Wilkinson