I can name at least one. It's a stretch knit fabric. Which means the armor will sag and pull away from your body when you attach it to the vest. The vest is one soft part that's hard to find an easy way around. Fortunately, they aren't that expensive. TK409 sells em for about 65 a pop if I remember correctly. I'll probably be putting a few up for sale once I get my fabric in and can put up a good finished pic of my own, and will likely match TK's price. Mine will be padded and lined. I'm stll working out a resource for the fabric right now. Hopefully I'll get thru to the folks I need to talk to tomorrow.
If you want to see the prototype it's in this thread:
http://www.thedentedhelmet.com/showthread.php?t=9555
Ignore the pooch in the back. It doesn't have a full closure yet, it's just pinned on for fitting purposes. With a zipper, it fill conform to the curve of the back.
