Rumored by the Chinese Expreview.com site and spotted by Videocardz.com, the report suggests that Nvidia might release a fourth version of the GP106 GPU, the GP106-350, which could end up with 1280 CUDA cores, same amount as the GP106-400/410 based GTX 1060 with 6GB of GDDR5 memory, but pack 5GB of GDDR5 memory on a 160-bit memory interface.
Bear in mind that Nvidia already has three GP106 GPUs, which includes the GP106-300, which has 1152 CUDA cores and comes with 3GB of GDDR5 memory on a 192-bit memory interface, so the latest one could fill the gap in the lineup.
Since the report comes from Expreview.com, it is possible, and quite likely, that this will be exclusive to the Chinese market where those graphics cards are quite popular in cybercafés.