According to Videocardz, a custom RX 480 from PowerColor has been caught on camera. The most interesting part about this variant is that it connects to the power supply with a single eight-pin PCIe connector. With AMD's latest driver, and hopefully even a modified vBIOS and PCB, this should be plenty enough power for the GPU, even with overclocking.
Image Credit: Videocardz
The card itself is a three-fan design with three DisplayPorts, one HDMI, and a single DVI. This retains the reference design's three DisplayPorts, but also adds the option to use DVI without an adapter. I'm not sure whether all five connectors can be used simultaneously, which isn't too bad — apparently the GTX 1080 also cannot use all five connectors at the same time, so I wouldn't plan on connecting five monitors to a single-GPU system, just in case.
No pricing and availability yet… this is just a picture. We don't even know clock rates.