Hi Randy. Sounds like a nice project if you're making the suit from scratch. I was around the suits quite a bit during my military days and what I remember was a variety of material was used in the making of the suit, depending on the terrain it was supposed to model. I remember at least 4 different types, though I'm sure there were more, and they probably look different from when I was around them in the 90's.
There's a ton of info on the web, of course, so you should have quite a bit of research material to choose from. As for modelling the suit, it depends on the type of suit. Most suits are made up of strands of material, like string. You could probably get away with threads of varying thickness and lay them individually. It would be a time consuming process but the results would be very nice. You could also use very thin, narrow strips of paper. I would probably use some kind of tissue paper since it will lay better. For either medium you could mix up a water/white glue concoction to make them materials lay naturally. After drying the suit could probably be painted.
I hope this helps. I'm more of a ship builder myself but saw your thread and it got me thinking. Good Luck. When you start make sure you post picks. I'm interested to see how you do it.
Phil