Over at Sunshine and a Summer Breeze, Michelle did a series of posts about putting together an Avengers-themed birthday party for her son last year. She made a piñata that looked like Captain America's shield, character masks for all the kids and, naturally, a cake decorated with the Avengers. Take a look at the cake, though...
Now, she used a coloring book image specifically because there were extra bold outlines and the coloring wasn't complex, like you might get with a modern comic that she may have had ready access to. But the cool part is that you don't actually need to wreck the original image to create the icing version. Which means that you could use actual comic books from anywhere in your collection -- including ones from several decades ago when the coloring was more simplistic. You could cheaply and fairly easily put anything on your cake from the likes of Jack Kirby or Curt Swan or Carl Barks or Charles Schulz. You might have some difficulty if you tried replicating the intricate details of something from a guy like Hal Foster, but most comic artists wouldn't be that hard to copy, I don't think.
And, of course, you wouldn't need to limit things to a single image -- you could replicate whole comic sequences and/or use multiple covers and pin-ups to create a mash-up of several different characters. Without needing to do any combining of the images in Photoshop or anything. The method she uses for the cake transference thing here is pretty old school, so you don't need any fancy tools that you wouldn't already have if you were baking a regular cake.
Like I said, I just thought it was really clever and wanted to share.