We had the chance to review the old Kudocase a while ago. It was a solar iPad case that was capable of converting indoor and outdoor light to energy for iPads. The case was quite thick and heavy though. It seems the product maker is now planning to release a much improved version of this case for the iPad 4, iPad Mini, and Nexus 7.
The KudoSol case will have a solar panel and a 5,400mAh battery inside. The case can serve as a movie or keyboard stand for your tablet. You will be able to charge your phone using this case too. The product is not shipping yet but lets hope it delivers. You can keep up with this project on Kickstarter.