All these examples use sensors developed for x-ray imaging though the use of a scintillator, converting X-rays to visible light, which is then imaged through standard light sensitive materials. Either a CMOS, an amorphous silicon or yes, film.

The reason for the low resolution is the size of the individual scintillator crystal matrix, the latter is not very high resolution to start with. Some are working on smaller but it takes many years to fab a next generation.

There are quite a few manufacturers other than DALSA making large chips. Sony puts as far as I know more large DSLR and MF sensors out than anyone else. The X-ray sensors are made by houses specializing in that application. (I used to work for one and run a CCD department ... )

Although I would love to shoot digital with 4x5 and 8x10 sensors, I don't see myself forking money out for one at the current announced resolutions. It will be somewhat affordable but I don't see the point on shooting 12MP images on a 8x10 digital sensor.

Doesn't make sense for my workflow, it may make sense for others.

YMMV

Rudi A.