Clean and wash beans. Soak in a large pot overnight. When ready to cook, drain off water. In a heavy 4 litre pot or dutch oven, heat the bacon fat. Saute onions until wilted. Add the beans, tomato sauce, salt, pepper, vinegar, Tabasco, red pepper, and thyme. Add enough water to cover the beans. Simmer until beans are semi-cooked, about 30 minutes. Remove 1 cup of beans and drain. Mash in processor or blender. Return mashed beans to pot along with ham hock and cook over low heat for 2 hours, until the mixture is creamy, stirring occasionally. (The beans should be creamy and juicy. Toward the end of cooking time, if the beans seem to dry, add a little broth or tomato juice.) When done, remove ham hock. Remove meat from hock and return meat to the pot. Stir to mix. Evenly divide the rice into 6 individual serving bowls. Spoon the beans over the rice. Garnish with chopped onion, Tabasco sauce, and cooked sausage slices. Serve with French bread.