One of the lower end Better Light cameras backs such as the one shown at http://www.betterlight.com/pages/prod_4000.html
are likely to do the job for you. 19 MPixels for only US$12,000 plus the cost of the camera and lens. If you need more than that, they do have a model that produces an 85MP image for US$25,000.
How good do you need the image:-?
If you will be satisfied with the output of "normal" digicams, one issue to look for beyond picture quality is a remote shutter release. Watch out for the infrared wireless remotes, some of them will only work from directly in front of the camera. Nice for group shots when the photographer is part of the group, but not so nice for other uses.