It is possible that a shipping invoice fragment was leaked for the NVIDIA GeForce GTX 960. Of course, an image of text on a plain, white background is one of the easiest things to fake and/or manipulate, so take it with a grain of salt.
The GTX 960 is said to have 4GB of RAM on the same, 256-bit bus. Its video outputs are listed as two DVI, one HDMI, and one DisplayPort, making this graphics card useful for just one G-Sync monitor per card. If I'm reading it correctly, it also seems to have a 993 MHz base clock (boost clock unlisted) and an effective 6008 MHz (1500 MHz actual) RAM clock. This is slightly below the 7 GHz (1750 MHz actual) of the GTX 970 and GTX 980 parts, but it should also be significantly cheaper.
The GeForce GTX 960 is expected to retail in the low-$200 price point… some day.