re: synthesized color versus calibrated subtractive color
"Many people have used the altitude and image sets to produce landscapes of Mars, and there've been a couple of interactive "flyable" programs. But I don't think anybody's converted the data to a format MS FlightSim could use, and that would be hot. "
X-Plane has global Mars Scenery available and some might argue it's a more realistic simulation than FS2004.
Also - check out www.polygonworlds.com for the Mars Explorer 3D - (spot my wonderfully modelled mars-plane when you do :D )
Doug