Asian website chiphell have what they claim to be a picture of the GeForce Kepler 104 (GK104) reference PCB shot.
The card is equipped with a 5-phase NVVDC configuration, as detailed in an older article. It also confirms that the GK104 has a 256-bit wide memory interface, with likely 2 GB standard memory amount.
While the PCB is green in color, it's obiously an early engineering sample. The final product (branded GeForce GTX 680 / GTX 670 Ti) will likely have a black-colored one.
It's a bit of a weird photo with stuff chopped off, but have a peek.