Slightly off topic, but I found a bivy that used to have a reflective coating. It'd be interesting to find out why they got rid of it. I imagine it's because the coating was rubbing off and making shiny sleeping bags.
http://www.titaniumgoat.com/Bivy.html

@Tango
I'll gladly share when my plans firm up more.
_________________________
www.eugeneleafty.com