Pete, The keychain idea may be your best bet. How are your simple painting skills? If you cut the iconic mickey symbol of 3 circles forming the face, or a skull and crossbones from Pirates of the Caribbean out of thin plywood, you could just paint Mickey black and use black & white on the skull. Stack cutting a simple outline wouldn't take a lot of time. Drill a hole in an appropriate location for the chain. I may be wrong, but I don't believe you can get in trouble for something like that if it is just given as a gift and not exchanged for any value.
Just thinking out loud here, but I wonder if you couldn't purchase stickers or decals that could be adhered to a simple cutout to reduce painting time?