Back when I lived in the great white north and rode my bike all winter I bought a pair of full leather work gloves with a very thin lining and sno-sealed them until they were absolutely waterproof. They worked great. The key is to keep your core warm and your core will keep your hands warm so the gloves don't need to be well insulated, they just need to block wind, rain, and snow and to keep your fingers from sticking to your handle bars.