BHEOFILUDS. BRS is awesome. That would be awesome.
Well, a good place to start is what we were planning for our Warhammer armors (of various kinds). It works out for a multitude of kinds of armors, from plate armor, to flak vests, to power armor. Not only have we been working with it, but we've got a friend who showed us the methods and we've seen his results, and they are awesome. It's called "ABS Foam" I think. Also try "utility foam", or something like that at hardware/car stores. It should come in about three or four squares in a package. One side should be smooth, and the back side of the squares should be textured with a weird hatched texture. (like those metal things on trucks and shizz that have the little diamonds). There's a lot more info I can help ya with. Let's hang out sometime and Jan and I can totally help you out! It's really amazingly simple, but it's easier to show/tell in person. XD