An added source to my conjecture: https://www.eoshd.com/2018/09/panasonic-full-frame-mirrorless-camera/
The most impressive camera I've shot with this year is not the Sony A7Riii or the Nikon D850. Without a doubt it's been the time I've spent with the Panasonic GH5S that's made me sit up and take notice. It's pretty much perfect for shooting video and I'm happy with the noise performance up to 3200 ISO; maybe a little bit past.
But as I was laying in bed, counting 50mm lenses in my head, trying to get to sleep in defiance of my insomnia, it came to me that what I'd really like to see in a new camera would be all the stuff that's in a GH5S but with a full frame sensor. I could care less about actual resolution. I would not even care if it was a 10 megapixel sensor as long as it featured dual ISO (lower ISO = great dynamic range; higher ISO = low noise and nice files) and shot the incredibly beautiful video that I'm already getting out of my current GHS. These guys get the idea of hybrid camera technology, and use, better than any of their peers right now.
Can you imagine a beautiful GH full frame with glorious and gigantic 10 µm diameter pixels? With incredible color science, minimal noise and 400 Mbs video files, in camera!!! Sure, the camera would still only have 10 to 12 megapixels but the files would look incredible, and never mushy.
I read the rumors and some people were suggesting that since Panasonic and Leica are partners that the lens mount would be the Leica SL lens mount which would give access to a small but highly respected group of modern lenses. But I'm equally sure adapters would abound.
We've seen the Nikon Z introduction and I think it's pretty darn good for photographers. We're all pretty sure Canon is about to drop their mirrorless miracle on the 5th of September and even Olympus seems to have something up their sleeves.
I'm predicting that what happened to film cameras between 2002-2005 is about to happen to traditional DSLRs remaining in the market. They'll be gone as new stock products the minute mirrorless sales jump the line. Traditional camera users will be as vehement in their resistance as their kind were when facing the onslaught of digital during the waning years of film photography. They will kick and scream and prognosticate about how DSLRs will take decades to recede. But then we'll be reading their blogs three years from now as they tout the amazing capabilities of their XXXXXX brand camera. More telling will be their gushing praise and total allegiance to electronic viewfinders. Brace yourselves DSLR users, you are about to be hit by the wave of EVF. Resistance is largely futile.
Don't like EVFs? Better stock up on (now) retro gear. Those D850s won't last long. That is, if we can actually get them out of backorder status....
Just passing along rumors. Don't want you to go on a Z shopping spree if there's something much better just around the corner.