These rumours have been around for a while, and are completely delicious. They are also of somewhat low probability, and I say that as someone who has never found I camera I loved in the digital era the way the Mamiya 6 and Fuji 690s held my heart.
To be meaningfully useful, these cameras will also have to be EVF-based, as you just won't get sufficient focus accuracy on a traditional RF to make use of the ultra high-res.
But who knows, maybe there's a miracle in the offing. Personally, I think a 46-54MP 35mm Sony-cam is what's in the offing. A9r or something like that.
- N.