I haven't read all the comments, so I don't know if someone already pointed this out, but if you look at the two bare PCBs you can see where there are actually places for a sixth phase on the power supply, and a spot for a second 6-pin power in, as well as a spot for another capacitor next to that second 6-pin.
So... This is complete speculation, but it kinda looks like the PCB is ready to be used for another card a step above the 1080 even, which means that nicer card would also use the same GDDR5X ram (since HBM2 would need a completely different layout) and a little more power with a second plug.
So are we looking at the 1080ti using the same PCB and ram but with more power? Or the next Titan? I'm guessing the 1080ti, since the next Titan would be using the GP102 and probably need a different PCB. But if it were the same PCB for the Titan, then that would confirm that the Titan will be using the same GDDR5X ram instead of HBM2.
Thoughts?