It seems none of the companies that make protective covers for devices with standard-size batteries are interested in protective covers for devices with extended-size batteries. That's a terrible business decision! The increased battery use of our phones make extended-size batteries very popular now. Those of us who use them are a growing market, yet we're an overlooked market. Hyperion has a TPU protective case for its extended-size battery (available on Amazon) for $9.99), and it comes in various colors. But will it fit other companies' devices? Looks like it might, but not a guarantee. However, I haven't seen any other such cases offered by the companies who specialize in them.
Wake up! This is missed revenue, companies! A growing market that will continue to grow as devices require more battery power with every system update and larger screen sizes.
EDITED: I just checked the reviews of the Hyperion case on Amazon, and it seems to leave a lot be desired from even the users with Hyperion batteries. So, if any of you tries one out, please post and let us know if it works on your phone. Personally, I have a Gorilla Gadgets extended-size battery (white).