Certainly the original elements of the 5 travelogues and two story films could be converted to digital. But why? The original film elements are extremely sharp - better than most 35 mm films, and digital conversion would make them less so. Resolution still ain't up there with film. In the old days, the film projectors would display some jiggle. Each panel would also sometimes have a slightly different color, particularly in the blue sky. These kind of problems are "fixed" in DLP projecttion But nowadays, standard film projectors can be rock solid too and color balancing is better. The new "This Is Cinerama" print to be used late in the year at the Hollywood Cinerama Dome is said to have excellent color uniformity. I'm looking forward to seeing it.
P.S. If you're talking about the bogus single camera/projector "Cinerama" films, the original 70mm elements would provide better resolution in film format than current digital technology.