Attached to the plastic iPhone 4-holding shell is a flip-open mirror that’s slightly larger than the iPhone 4’s screen. Think of it as a digital update to a makeup compact, hinged on one side and connected with a plastic clip on the other. Built into the back side of the mirror is a card compartment made for two or three credit cards or IDs; a thumb-sized hole allows the user to slide them out when needed. We can see how this could be…