Sometimes details about new hardware can be found in the least likely of places, such as in a paper about instrumentation and methods for astrophysics! The Institute of Space Science and Astronomy (ISSA) of the University of Malta investigated the suitability of NVIDIA GPUs for signal processing and it turns out that one of the authors of the paper (PDF) is Mike Clark, a Compute DevTech Engineer at NVIDIA.
One of the interesting things this paper reveals is the codenames of two upcoming high-end GPUs from NVIDIA; the GM200 and GP200. The GM200 is a big-chip Maxwell, it's expected to arrive towards the end of this year and promises theoretical performance over twice as high as that of the GK110 (Kepler).
The paper also talks about the GP100 "Pascal" GPU, this chip is expected to hit the market in early 2016 and promises almost three times the performance of the GK110, or about 40 percent more than the GM200.