Gimbling the image sensor would have interesting technical problems, like where do the wires go. But square format? BlackBerry tried it, and those of us who loved our Mamiyas and Bronicas thought it was a good idea. Sadly, very few people did. And with more than 90% of the world’s monitors a long rectangle, it’s not going to change.
But it is interesting how the advent of the laser printer and the LCD monitor have actually reduced the variety of image formats and framing, just as the iPhone has drastically reduced the variety of mobile phones.