The Official Vega Partner Board thread.

Apparently a false rumor:

On Tuesday , the German branch of Tom's Hardware reported that Gigabyte would not work on a custom RX Vega 64 card. A reliable source, however, showed Hardware.Info that there are indeed custom RX Vega 64 cards from the company. There would even be several models. According to the source, the first of them should be in stores in week 42 or 43, a period running from 16 to 29 October.