Well the ones from 02 are Carbon Black to which suits me fine as if it was any other colour i would have had to buy the Carbon Black covers as it's the colour i would of wanted. Also except for the battery door i don't really see how the backs are easily swappable either. I actually have a feeling when production is in full swing you choose your colour and are then stuck with it where as originally i thought they where going to be swappable.
Samsung Galaxy S3 Pebble Blue 16gb, Rom Super Nexus JB 4.1.2 Build5
Motorola Xoom UK ICS 4.0.4 32gb 3G +32gb SD Card
The only problem with common sense is that it's just not that common.