I use the nomex ones for work. We get them from:

http://www.flightsuits.com/

They aren't the warmest things in the world, but they do maintain dexterity.

You might try layering some wool fingerless gloves on top if it gets
really cold.

Word of warning on Nomex from ebay - depending upon how the previous
owner warshed and cared for the product, it may have lost its fire
resistancy.

Helen