ΑIf one screen is not enough for you, ZTE with the Nubia Z18S seems to offer you its own implementation with 2 regular screens.
A video that has appeared on the internet, shows us a fully functional device, which in addition to the front Bezel-less screen on the front, has an almost full screen of about 5 inches with an aspect ratio of 18: 9, on its back device.
Now if you tell me that this is perhaps an exaggeration, I will agree in part with you, but no matter how we like it, these are, and it is good to have many options to meet all our consumer needs.
Of course, such an implementation, no matter how we do it, will be the nightmare for the battery and the autonomy of the device, as from the Video the screen seems to look like amoled or IPS, which means that it has energy needs no matter how we do it.
What saves the situation in terms of autonomy, is the fact (as shown in the Video), that this screen is activated only when the user turns the back of the device towards him, while at the same time the front screen is deactivated.
This means that the device may have better autonomy than we think, since depending on the use of the screen chosen by the user, the energy needs of the device will follow.
We can not say with certainty that the above device will eventually go into production and distribution, or it is just a Demo Project of ZTE-Nubia, but anyway we will let you know what we learn above.