Many of us carry around several every day items: 1 - A phone 2 - A wallet with money cards, ID and some loyalty cards 3 - Keys If you don't have a smart phone then you might also carry a camera, an iPod and other gadgets. The advent of the iPhone enabled users to carry just one device. Some apps allow you to reduce the amount of cards you carry in your wallet. It's likely that iPhone 5 will introduce a form of wireless payments offered by credit card companies and banks to further reduce your wallet. This thread deals with #3 - Keys. In an effort to further minimize the items I carry with me, I'm going to try to turn my iPhone 4 in to my house key. I've begun doing this by changing the locks in my house to RFID. The technology allows you to wave a key fob in front of the lock and the door opens. The back glass on iPhone 4 is extraordinarily easy to remove so I thought that I might find room behind the glass to slip the slim chip. the chip and its antenna is about 1mm thick and the diameter of a quarter. Unfortunately, Apple has engineered the new iPhone as tightly as possible. The glass presses up right against the battery so the case didn't close. I'm trying to keep the iPhone naked but as a last resort, I'll use a case to hold the RFID in place. My next attempt will be using a 3rd party glass back replacement. Has anybody purchased one of these? I'd be interested to see if they have more room. All I need is 1mm. This brings up the idea that a case manufacturer could be successful selling a case with room inside for multiple RFID's and even a credit card. Any ideas? Anybody attempt to do something like this yet?