Harry Callahan
Member
I recall watching a video that CBC did a while ago (proably 4 or more years ago) , I think they had someone interviewing the two main folks at IMAX. But my google skills are not up to the task of Locating it
A quick search led me to this:

IMAX Next-Gen 65mm Film Cameras: All Details - Y.M.Cinema Magazine
The lecture titled “The Art and Science of IMAX” sheds light on the upcoming new generation of IMAX 65mm film cameras. All details are below

Seems like they`re even bringing such cameras back. But:
"We did a lot of research and we were looking at designing a new movement and we couldn’t do any better and this camera is about 25 years old. It’s the original camera this is actually the newest model of the camera and it’s 25 years old [MSM 9802]. The original ones were built I think in the early 70s but the movement remains basically the same. It was a stunning piece of machinery to do that. So we figured if we try to redo it from the ground up, we’d probably screw it up. So basically we’ve designed the parts around the movement to be better and more stable and more reliable."
Seems like the movement has not changed since the 70s.
Maybe vacuum suction was/is used for better film flatness, but film transport seems always to have been done by a claw.