the only reason they dragged out the 6ft for the movie was because the 4ft, which was vastly more detailed, had been modified with all the AGT crap, and the movie was being shot right away. They basically painted up the flat hull of the 6ft to try and make it look as detailed.
Ahh, that hideous monstrosity (the AGT Gal that is). There's actually some quite interesting pics on st-bilder of all the bits they added on.
personally, i'd extrude the escape hatches softly.
Trouble with that is, after several hours of experimenting, I've yet to find a method that produces decent results while keeping the mesh somewhere near clean. Normally I would use boolean, but I'm trying to go without it for the entire model.
Looking at the comparison pic on EAS gave me (what I think is) a good idea. Once the entire saucer is finished with the MeshSmooth applied, I'm gonna apply a greeble modifer. It's designed for making city scenes, so extrudes faces to different heights. If it's done subtly enough, and on the right faces, I think it could reproduce the bumpiness seen quite well.