Still no idea when these are coming out, or how much they'll cost, but EVGA will introduce their own custom SLI High-Bandwidth (HB) bridges. These are designed for the GTX 1080 and GTX 1070 cards in two-way SLI mode to share frames in high-speed 1440p, 4K, 5K, and Surround configurations. As TAP mentioned on our live stream, if the bridge was overloaded, it would fall back to communicating PCIe, which should be doing other things at the time.
NVIDIA's SLI HB connector.
We didn't have a presence at Computex, so you'll need to check out Fudzilla's photo for EVGA's.
As for EVGA's model? Without pricing and availability, all we can say is that they have a different aesthetic from NVIDIA's. They also, unlike NVIDIA's version, have RGB LEDs on them to add a splash (or another splash) of colored light inside your case. Three versions will be offered, varying with the distances between your cards, but, as the SLI HB spec demands, each of them only supports two at a time.