If you think transparent smartphone is a thing of the future, then the future is not far away. In Taipei, Polytron Technologies is building a transparent smartphone and they have actually had a simple prototype as a proof.
If you are thinking about those transparent smartphones you saw in movies, they are not quite there yet. For example, some components are not transparent. You have to take care of the card slots (MicroSIM, Micro SD), battery and some other components.
In the demo in this video, it shows a glass panel with built in camera, Micro SD card slot, SIM card, microphones and some connections powered by two button batteries.
As you can see, it is still in the infancy stage. However, in the video, it was mentioned that a full working one will be available end of this year. Super excited to see such technology unveiled within this year.