Apple has released their detailed iPhone 5 blueprints for case manufacturers looking to build new accessories for the latest iPhone. You can check out the detailed .PDF here, which notes highly detailed dimensions.
The drawings are part of Apple’s developer resource page (which currently is open to the public) for case designers looking to make accessories for the iPhone, iPad or iPod touch. You can check out the dimensional drawings for every single iOS device and iPod here.
Note to self: Keep these away from Samsung.