ZTE has actually delivered such a device, Samsung is expected to do so by the end of the year or early 2019, and now LG has also weighed in with their own design, revealed in a patent application.
The device features a fully foldable single-piece screen with a very small bend radius and appears to be quite narrow when folded.
Alternatively, it may have a movable cover which reveals a small display.
As usual, patents are not proof a device is on the way, but it can be guaranteed that if Samsung leads LG will follow.
The full patent, which was filed in July 2017, can be seen here.