Hey Roocketman,

There is a water proof and breathable membrane that we all have used -- skin.

I first used vapor barier technology as a Military Policeman. A dry cleaning bag over pajamas (yeah cotton) then the regular wool uniform. Worked great. A sandwich of cotton T-shirt, dry cleaning bag and cotton hoodie was great for a jog.

I carry and use vapor barrier technology hiking 3 seasons. A sandwich of regular socks, produce bags and fleece socks keeps my feet warm.

There is no commercial reason to promote vapor barrier use. One of the best is an emergency rain suit sold at Wal*Mart for about $6. The competition is a $250 high tech parka.

Vapor barrier clothes work great when you level of physical activity is constant. It requires frequent layering for most activities.
"In theory, theory and practice are the same. In practice, they are not."
Yogi Berra