Preheat oven to 350 degrees F.
In a skillet over moderate heat, add the oil. Heat the oil until hot, but not smoking. Add the onion and garlic and cook, stirring, until softened, about 5 minutes. Set aside and let cool.
In a mixing bowl, whisk the eggs, milk, mustard, and hot sauce together. Add marjoram, thyme, salt, and pepper.
In a large mixing bowl, combine the meats, egg-milk mixture, bread crumbs, parsley, and the cooked onion mixture.
In a small bowl stir together ketchup, sugar, and vinegar. Set aside.
Form 1 tablespoon of the meat mixture into a small patty, add it to a small oiled skillet, and cook until no longer pink. Taste for seasoning and adjust.
Transfer meat mixture to an oiled loaf pan. Brush meat with ketchup glaze.
Bake in oven for about 45 minutes, until glaze has set. Brush meat loaf with remaining glaze and bake for 15 minutes more. Internal temperature of loaf should be 160 degrees F.