I have heard that chessie/lab crosses make great hunting dogs because they can hunt upland like labs but retrieve ducks from icy rivers all day long without getting too cold because they have oily hair like chessies. Can anyone shed some light on this subject? Also, has anyone ever heard of someone who breeds for this mix?

Why get a cross ? If you get a pure lab from a good line they can do a good job on upland and if they are bred correctly so they have a good coat they can retrieve and break ice also. The same is true of a Chessie. When you get a cross you will never know if the dog will retain the coat ie oiliness or not. I have a Lab with a good coat and he used to break ice but now he is retired (too old)and I again have a Chessie.