I dont understand the obsession with square digital format requiring a square sensor. It's called cropping! I have clients who like squares, and that is what we do. I have a square crop on my viewfinder, I compose the image to square and we crop the sides in C1.
The reason square format was chosen so many years ago by Hassy, and Rollie, was because their cameras had WLV, and it is quite difficult to shoot a vertical with a WLV without cropping. It was never meant that square was the format of choose for those cameras.
Also, since we now live in the digital realm, the "no cropping" rule also makes no sense. Once again, this principal was more about practicality, not a strict working style never to be violated, since if your image went to print, articulating the crop to the printer making the mechanical/plates would be very difficult. It was just easier to shoot without cropping, but now ...