lurker77 said:
EDIT: My mistake. 12 megapixels is not the same thing as 12,000 pixels per line. That would be 48 megapixels, beyond what any off-the-shelf camera can do ATM.
Not sure what you mean by off-the-shelf, but there are a few medium format digital cameras in this range available today or even as of several years ago.
They will set you back a few tens of thousands of dollars, but probably still much less than the pro equipment (which I don't know anything about).