I've been sitting on this one for a long time, but recently started it up again. Just trying to do the landing pad seen here:
I started in 3ds Max but then moved into Zbrush to use the IMM tools and the new polymodeling tools to speed up the creation of the flat greebly areas. That's about the best reference I can find and no one has really done a very good and accurate model so I'm just kind of winging it a bit as I go and trying to get the general form. I made some of my own IMM brushes and am using some of ZBrush's standard greeble IMM brushes as well.