The Microsoft Applied Sciences Group has built a gesture input concept using a transparent OLED Display.
Under the project title "The Wedge", Microsoft is tinkering around with new display technologies.
A camera under the transparent OLED display is capturing the user input. The use can still see information displayed on the OLED screen. There is definitely potential to have the input capture behind the display surface. Watch the video below to see this concept in action.
More details on the Microsoft Applied Sciences site. Via OLED-info.