Thanks Ebrahim. A photo of Canon’s new 8K camera system (development announcement) sent in by a CW reader. He says:
Body is identical to C300II but it records externally using an intermediate module then to Four Odyssey 7Q+ 4K recorders (Four 4096×2016 signals making up DCI 8K) up to 60p.
Can’t say with 100% confidence that it is the real thing. But I guess it is. The photo was posted on Imgur.