An iPhone Case was announced by Vooma and called it “Peel PG92”, case for iPhone 4 that adds Dual SIM capabilities, according to TechCrunch.
This Device itself consists of a back-up battery that can charge your phone and what ammounts to a dumbed-down cellphone. After you jailbreak your iPhone and download the Vooma App, you can easily control the phone inside the case to make calls using a SIM Card Dual Mode. Which charges, Unlocks, and enables Dual SIM’s for your iPhone. Turn your Phone Into a Full-Blown Pocket Projector with This Case.
For more details on this iPhone 4 Case which adds the Dual SIM Capabilities to your Phone, please head over to this link here.