I was in Alaska a few months ago and was looking for extremely cold weather gloves for our 4 wheelers. I found one pair rated for something like -40 below. They were 63.00 if I recall. No I didn't buy them.I went to a Sportsman's Warehouses in Fairbanks and one in Anchorage,I asked a couple of the guys there. They recommended a rubber(Neoprene)fishing glove made for cold weather fishing.We bought a couple pairs of them but to be honest we haven't needed them yet. I've tried a pair of the supposedly cold weather gloves Cabela's sells. They aren't worth a darn.
These fishing gloves were around 20.00. They are thin but made of a water proof rubber that's water tight until you put holes in them LOL.Like I said two guys that worked there recommended them. One was a avid fisherman and he swore by them.
Everything in Alaska is very expensive and I mean very expensive. I don't know who would carry these -40 below gloves in the lower 48. I'm sure they would gladly ship them to you.I might add they had several different cold weather gloves in the store. I took a few minutes to look in their catalog on line. The site is updated to 09 but the catalog tab says 2004-05 catalog.I would suggest calling or emailing them.
Here's a link to where I found the -40 degree rated gloves.(in their store)
http://www.aihalaska.com/
http://www.sportsmanswarehouse.com/