I have some fishing gloves that are a combination of neoprene and fleece, I think they are 'Kenia' brand. More flexible than the neoprene I think they allow for better circulation. A buddy of mine likes to use the rubber gloves sold for dishwashing over a light fleece glove.

I'm not able to actually keep my hands dry while fishing, too much reaching into the water for fish or dropped objects. Instead I am trying to give my hands something insulating and warm so they can recover after a dunking.

You might try some of the disposable hand warmers used by skiers. These are little paper packets of iron fillings and electrolites than heat up when exposed to air, the cost about $1.25 a pair and generate heat for 6-8 hours. Avialable at most ski shops. They are small enough to fit inside your gloves, some ski gloves even have a little pocket built in for a hand warmer.