Preheat oven to 350 degrees F (175 degrees C). Lightly grease a roasting pan.
Mix venison, sausage, onions, and cracker crumbs in a large bowl until well combined. Add the evaporated milk, eggs, barbeque sauce, salt, pepper, and half of the tomato sauce; mix until evenly combined, and let stand 15 minutes. Place onto roasting pan, and shape into a loaf.
Bake in preheated oven for 30 minutes. Spread top with remaining tomato sauce, and continue baking for an additional hour, until the internal temperature reaches 180 degrees F (82 degrees C).
