Rick, if you haven't done so already, take a look at Stephenson's website. You can see how they make their shirt. It has some kind of "fuzzy" stuff on the inside, but sounds like silnylon. It's not all that expensive. I only mention them because they make everything, including underwear and have a big explanation of how it's supposed to work.

Jack Stephenson was a pretty strange guy from what I gather from people who knew him (his son runs the company now). Kind of a "true believer" "my way or the highway" kind of guy like Ray Jardine is about his stuff. Be that as it may, at least they have a detailed explanation for why what they sell is made the way it is. I have no idea if they are right, but at least they give you something to think about.

www.warmlite.com

Here's another write-up on vbl by a guy back East who posts on VFTT and TTips and has a good website on bc skiing.
http://home.comcast.net/~pinnah/DirtbagPinner/vb.txt