Maybe a little late to the party, given the Twitter announcement the other day, but here's the link:

https://www.amazon.com/dp/B07C7HWX9S

I had these made up at a local steel fabricator when I saw that there was a widespread interest in a product that fit this bill. I've got it on my Cintiq Pro right now, and it works great. I made a point of leaving the docking port for the Pro Engine open, which also helps with cable management.

Feel free to comment, critique, or question.