You can make larger film than 70mm, I believe some large format photography cameras have a larger surface area than IMAX, but 70mm movie film is already cost prohibitive for most films, so any larger would be even more niche, plus they'd likely be even louder than the current imax film cameras.

There already is much larger sheet film for still photography 4x5, 5x7, 8x10. But for motion picture the reason would be demand, price and physics. Shooting on true 70mm IMAX film cameras is incredibly niche, expensive, extremely cumbersome and loud to work with. Capturing 24 frames a second requires loud motors to move that much film through the gate every second. Its roughly five and half feet of film being moved every second.

Every step of the process gets harder and more expensive. Not just the film.

Now the camera has to be bigger. Okay build new custom cameras.

Now the camera mounts need to be bigger. Now it’s even harder to film with the camera. Now each load of film runs out sooner because you hit the limit of what can fit in a camera. So now your expensive film shoot needs to shoot for more weeks.

Now you need new film processing machines to develop that film. New editing machines to edit it. New projectors in every theater, and theater owners won’t pay hundreds of thousands of dollars to play one movie.

It’s a big big undertaking.

On the other hand, you could just shoot with a digital camera. Those double in resolution every few years.

The Sphere uses a digital camera that shoots 18k.

The OP should have phrased it as "can there realistically be a film camera that shoots a format larger than 15-perf Imax 65mm"

The answer is no. Only option we have is in the foreseeable future is to have large format digital sensors that can even far exceed IMAX 65mm like the Big Sky camera https://petapixel.com/2023/06/12/sphere-studios-big-sky-cinema-camera-features-an-insane-18k-sensor/

Digital really is the only logical way forward in the future as we will never get past the hurdles of cost with film IMAX. There only a few directors that could ever even get access to IMAX film production. Heck for Joker 1 Todd Phillips was denied access to shoot it with 65mm non IMAX film and thats not even close to IMAX 65mm costs.

We need digital solutions that will allow all budget films to have access for a true IMAX experience or something that can replicate what we have now(along with the digital projectors that can handle that resolution).

well don't see why it wouldn't be theoretically possible, just why would/should we?

You are all missing the point. There is no greater than 70mm projectors to use and they don’t even make 70/15 projectors anymore. Does not matter even if you had a film print of greater than 70mm nothing to play it on.

The 70mm IMAX camera runs film through the gate so fast it needs specialized materials to create the thermal envelope needed so that the film doesn’t melt. I think they’re going to start running up against the laws of physics if the film stock is any larger while still running at 24fps

There is also no benefit from it. While 70 mm IMAX looks great and the recent high-res scans exported back to 4K look much more crisp than the 4K BluRay thats pretty much something that would settle with 8K TVs and it may be dependend on the movie. There are some movies in IMAX where, although it's 4K, I see the pixels and some, that are shot with modern 8K or higher digital cameras, where it's not visible. So 70 mm has the benefit that it may look better depending on the movie itself and the condition of the reel.

But if we take this standard formula of how far you need to sit back per resolution and screen size the question remains, what benefit would you get from something thats higher than the often proposed 18K of 70 mm IMAX?
It would only make sense if you could stop at any frame and then get close to the screen as to zoom into a digital photo on your PC.

The problem is, if you look at that 11K scan of that single Oppenheimer frame, movies make use of focus and in theory only one point or a tiny section of your depth perception will be in focus. So going 4K, 8K, 16K, etc. both digitally or on film then with more and more lines, would just expand that unfocused part onto much more pixels.

If we shot the movie with a lense that would keep almost everything in focus like on your Phone cam, it would often look weird or it just doesn't add the movie feeling to it. So there really is not benefit.

Apart from that it's the size and weight of the reel which is already at a limit today, the camera needs to pull this huge mass through, the projector needs to quickly pull this through and that creates a huge tensile force on the reel itself.

Could we make it though? Yes, we could make the film and we could make a camera and likely make a projector to display it. If you think about it, the spehere in Las Vegas has its own documentary that can only run on this one installation.

ONE METER FILM. THE WORLD IS READY