Apparently, some hardware sites got their hands on an NVIDIA driver listing with several new product codes. They claim thirteen N16(P/E) chips are listed (although I count twelve (??)). While I do not have much knowledge of NVIDIA's internal product structure, the GeForce GTX 880M, based on Kepler, is apparently listed as N15E.
Things have changed a lot since this presentation.
These new parts will allegedly be based on the second-generation Maxwell architecture. Also, the source believes that these new GPUs will in the GeForce GTX 800-series, possibly with the MX suffix that was last seen in October 2012 with the GeForce GTX 680MX. Of course, being a long-time PC gamer, the MX suffix does not exactly ring positive with my memory. It used to be the Ti-line that you wanted, and the MX-line that you could afford. But who am I kidding? None of that is relevant these days. Get off my lawn.