Kensington's just-released PowerBack and PowerGuard ($60) are, as the photos suggest, brand new battery packs in the shape of semi-cases for the iPad and iPhone 4, respectively. Both use soft touch rubber and provide access to the devices' headphone ports and controls, while covering their Dock Connector ports and using pass-throughs for their speakers. PowerBack adds 5 hours of battery life to the 2010 iPads, using a flip-out rear kickstand to prop…
