I have Burton mittens with an inner glove liner. If I actually need fingers for something (like turning on a light) I can pull out a gloved hand and get the job done without freezing up. Then I stuff the hand back into the mits. For the bulk of the ride the mittens provide plenty of dexterity to work my brifters (the CX bike) or grip shifters (the hybrid).

There is no such thing as a warm glove. Your fingers will always get cold in the greatest of Gore-Tex, Thinsulate wonderkind gloves. Embrace the mit.