I asked the Vancouver MEC cycling dept staff about the "waterproof" gloves that they carry. Their advice opinion was that there is no such thing as a truly waterproof cycling glove currently available. Instead they directed me to the paddling dept for neoprene gloves such as these:

http://www.mec.ca/Products/product_d...=1243963893689.

Their opinion being that, though your hands will still get wet, neoprene will do a more effective job of keeping them warm while wet, and will dry quicker.