iPhone case manufacturer True Supplier has recently posted online a new hard-shell case for the iPhone 5, which features the same tapered design shown in the leaked iPhone 5 design document showcased by Macrumors.
With considerable outlay involved in the production of any new case, Chinese suppliers are obviously confident that the risk of having the design wrong is outweighed by the potential windfall of having cases available on launch-day.
Apple doesn’t usually supply designs to 3rd party manufacturers, forcing them to play catch-up once the device is announced.
[Update: New report from Reuters suggests minimal change to iPhone 5 design from existing iPhone 4 form-factor]