Hmmm... I currently have my site set up so that when a user changes their style sheet the graphics change, but the shape and style of the graphics are the same (just the color changes).
I kinda see where what you are suggesting would be useful, but only if you are willing to settle for graphics that are created by someone else. After setting up seven different graphics sets for 10 style sheets I'm sure that I wouldn't want additional graphic sets per style sheet!
