Excuse me while I go kick myself. That's a neat trick. You could extend the principle to make multiple badges, or buttons. Small texture maps, and a chain of blenders. Buttonmaps A and B go into Blender 1. Blender 2 combines the Blender 1 output with Buttonmap C. I used the same sort of chaining idea to make a 3-colour Trek-style uniform, which also used a different material style for one component (Babylon 5 is maybe a better example to use).