I've heard of people baking flour on its own - low heat, obviously, until it gets to that chocolate brown color. That'll give you the flavor of the roux with less fat. Chicken - go skinless and boneless, use reduced fat chicken stock... sausage isn't a necessity, just something I rather like. You could use shrimp, you could use just about any kind of seafood you like. And I suppose you could omit the rice.