MOST of the tents that have been used in extreme cold, as in Arctic and Antarctic explorations, i.e. Amundsen, Scott, Nobili, Nansen, Steger and the current Canadian Forces ARE of breathable material.

If, they were still available, the old Black's of Scotland or "Pioneer" of Vancouver, BC, tents made of "pima" cotton would be my FIRST choice for deep cold use and a Ventile one would absolutely rock....and cost more than a new Toy 4x4, I bet.

My choice for a tent to live in during extreme cold would be my Hilleberg Saivo, no question and with double poles, I would bet this against any tent available and I have used a few. It is quite air-permeable inside and vented so well that moisture has not been a problem....but, anything can happen.