It looks like the GeForce GTX 1070 Ti isn't the final card in the Pascal series! NVIDIA just uploaded a video teaser that shows off an upcoming video card. Around the 11-second mark in the video, you can briefly see a glimpse of the name of this product. It seems to be called NVIDIA TITAN X Collectors Edition, and that suggests this may be the new flagship model in NVIDIA's gaming portfolio.
The Titan Xp is already a full-fledged Pascal so we're not quite sure what this new model will bring to the table. Perhaps a special cooler design (with fancy LED lights) and higher clockspeeds? One thing is for sure, it won't be cheap.