Duck is traditional in cassoulet, as is pork fat, hence the bacon. Although
the fat would not have the smokey flavour.
And traditionally, the beans are layered with the meats with the final layer being a crust of fat on top. But I think that last tradition has moved aside for the more sane of us who can't take that much grease.
I believe that the meats vary depending on the region of southern France in which it is cooked...duck, goose, pork, mutton.
I'm making it today, with chicken (so much cheaper than duck! although these 2 in my backyard are being fed so well, they look tempting) and an extra smokey Polish sausage.
mmmmmmmmmarg