I use some like this for coyote hunting. Coldest it got was -33 last year and with thin liners my hands were fine.
I've run these for the last 4 years and the keep my hands warm in negative weather.
Tough Mitts
Our Tough Mitts in wool and leather are made to survive the stormiest winters. Lined with sherpa and made with Stormy Kromer quality.www.stormykromer.com
I have the OR down mittens... they are warm and easy to slip on but definitely not durable. I am nervous to even put my hand on the ground when wearing them.I was looking at some down mittens either from Outdoor Research or First Lite but am a little concerned about the durability.