This is a nice leather case from hardce.com with built-in CF card slot including battery.
http://www.hardce.com/htmlen/default.htm
*Genuine leather
*Built in 1800mAh Li-ion Battery
*CF Card slot type II
*Hardware battery replacement technology, Privileged usage of exterior battery
*Low consumption microchip inside, intelligence controls of discharge. over-charge, over-flow, over-puts protection. communicate with main engine and make it display exterior battery quantity
*Two-sided leather inside and out, brown color and black color optional
