While it is possible to up-res, the clients you mention typically demand the best image quality that you can muster. Medium-format digital backs are really taking over here, due to 16-bit image files, large (48mm x 36mm) sensors and as many as 39 million pixels. Depending on the subject you will also find medium and large format view cameras with scanning backs, multi-shot backs, or film (chromes) that are then drum-scanned.
People who do stupid things with dangerous substances often die! -me