Please read the archives...Please <img src="/forums/images/graemlins/crazy.gif" alt="" /> If one more person brings this up I'm gonna go 'n tar n feather them! <img src="/forums/images/graemlins/confused.gif" alt="" />

Now there's an idea! Has anyone tried tar and feathers as an insulator or top coat? <img src="/forums/images/graemlins/grin.gif" alt="" />

Not quite, but have you ever seen oilskin or japara? When I was in NZ back in the 80's, a lot of local raingear was cotton infused with some kind of oil or wax-heavy, but waterproof. When it wore off, you could just treat the fabric again and it would be good as new.

I have an Australian stockman's coat, like in the Aussie westerns. It is a treated cotton or light canvas of some type., the coating is some kind of wax, maybe parafin. The brand is Driza Bone, a well-known Aussie company.

There are still a lot of jackets and other clothing made from these fabrics; Yahoo turns up a bunch of sites for sellers and manufacturers. Nothing particularly lightweight, but my stockman's coat is incredibly tough and fun to wear on occasion.

Here is an interesting story about the history of oilskins on an online store's site that I found.
oilskin history
Don't get me started, you know how I get.