Apple are allegedly working on Haptic Feedback technology for the iPhone, iPod Touch and iPad. This rumour originated just before the release of The New iPad and it definitely seemed credible since the invitation said "We have something you really have to see. And touch." with a picture of a finger hovering over the device's touchscreen. Unfortunately this didn't come to fruition but the iPad 3 sure came with a gorgeous display nonetheless.
“today’s surprise invention packs a punch with a wildly intelligent multi-tiered haptics system. The system will actually allow an iDevice display to deform so that it could provide the user with a button, an arrow or even a geological map to physically pop right out of the screen to give it 3D depth. If that wasn’t cool enough, Apple’s patent discusses a flexible OLED display that could be used for video glasses.”