Do we really need transparent displays on mobile devices?
Regarding transparent LCDs on mobile devices, you could fake them:
When you hold the mobile device in the air, they can just have a camera at their back and display what the camera sees with superimposed contextual digital information (Augmented Reality). See Intel’s OpenCV Computer Vision open source library regarding Computer Vision.
If the device is placed on a MultiTouch projector surface (like Microsoft Surface), the surface can recognize the device’s proximity and its visual boundaries (using the FTIR technology that can recognize IR light changes on a surface using a camera) and can talk to the mobile device to send it the image of what is displayed (or what was supposed to be displayed before if a docking placeholder is displayed when the device touches the surface) on the surface under the mobile device, and the mobile device can be clever enough to display what is streamed from the surface device to it, making it seem transparent.