I too have to use mitts in the winter. However, what I now do is just use regular paddling gloves like NRS and I use a waterproof over-mitt over them. It works great plus If I need my fingers, I can pull the gloves out of the mitt in seconds. There's lots of waterproof overmitts at places like campmore. I have a brand called Outdoor Reasearch and mine have robberized palms. I have also used NRS paddling mitts that have worked well for me too.

http://www.rockywoods.com/Fabrics-Kits/Shell-Overmitts-Gloves-Kit/Controlled-Exposure-Shell-Overmitts-Gloves-Kit-Black

http://www.amazon.com/Swiss-Waterproof-Weather-Trigger-Mittens/dp/B002UC3NW8/ref=pd_sbs_sg_2