Alan, the hood comes off my big TNF parka, but I don't think I'd want to try sleeping in it.

In really cold weather, the wintertrekkers who are pulling heavy sleds or toboggans seem to be wearing just some fleece or wool with an anorak over it, even in -20C or colder, until they stop. Their goal is to avoid sweating and soaking their clothes from the inside, so to speak. That's why they wear those cotton anoraks-because Goretex won't breathe very well at those temps and sweat won't transpire through the fabric like it will through cotton.

NOTE-I am talking about trekkers who are using cotton shells only in sub zero temps, not cotton for insulation, base layers or for use above freezing as an outer garment (jeans, hoodies, socks, t-shirts, etc.) This is based on my reading on a deep winter camping website, not personal experience. I don't even wear cotton briefs when I go camping in winter.