A new report suggests Apple is developing multiple iPhone prototypes, one of which sports a slide out keyboard. Taiwan-based Apple.pro reports that Apple is working on three iPhone prototypes, two of which are mentioned in the report. The first features a side-mounted slide-out keyboard; few other details were provided. The second is said to be very similar to the iPhone 4, but with performance and battery life improvements, similar to the jump from the iPhone 3G to iPhone 3GS. The latter is also said to have an upgraded camera; the report claims that both eight and twelve megapixel sensors have been considered, but the eight megapixel sensor is preferred due to storage concerns. The next-generation iPad is also mentioned, albeit briefly, and is said to be thinner while featuring a built-in camera.