Many years ago I bought some overmitts from REI and some big fluffy fleece mitten inserts. They are my go to when it is really cold.
I got them oversized, allow for my hands to warm up, and big enough to throw in a hand warmer easily. Although I hardly ever use warmers.
I tried to search and find links to what I actually have, but I guess things have changed.
But after all my research, it seems that the Outdoor Research Meteor Mitts seem to be very close.
This is pretty timely for me. I think I got a minor case of frostbite 2 weeks ago. Still have a little tingling in a couple of my fingers. Spent too much time unhooking a gut hooked bass, paid the price. Won't be heading to a tip up without my pliers for a long time.
George