Yes, you read the title correctly because the most expensive iPhone 4 accessory has just been revealed by Frank Muller which is a Swiss watchmaker. It is just an iPhone 4 case but a rather expensive one. As you can see from the photo below, there are a total of 6 different designs for the iPhone 4 cases and these are only available as Limited Edition iPhone 4 cases.
Since these are limited edition iPhone 4 cases, Frank Muller will only be releasing 500 units for each design making it a total of 3000 units worth of over $3.8 million. If you have some extra cash and we mean a lot of extra cash and you are willing to spend over $1000 for just an iPhone 4 accessory then this might be the product for you but it is would be quite a task to make people spend that much amount for just an accessory.
Currently these Frank Muller Limited Edition iPhone 4 cases are available on pre-order in Japan for 105,000 YEN which roughly equals 1,278 USD.