It looks like we won't be seeing any custom Radeon RX Vega graphics cards until at least the end of October, and probably more into November.
According to Hardware.fr who reached out to AIB partners making custom Radeon graphics cards, and said that no manufacturers are ready apart from one unnamed manufacturer who said that they're waiting for Vega GPUs to arrive.
If AIB partners are still waiting for Vega GPUs, then the custom Radeon RX Vega graphics cards are still many months away, with a November launch making sense. Remember that I posted a world exclusive scoop on there only being less than 16,000 x Radeon RX Vega graphics cards in the months post-launch... and here we are.
We have no official sales numbers on Radeon RX Vega from AMD just yet, only that it has been a great launch (like AMD would come out and say a launch has been bad, no company would). Here's what problems we have right now: