1. Prepare Meatloaf: Preheat oven to 325°. Pulse chopped bacon 4 to 5 times in a food processor until finely chopped. Combine bacon, pork, and next 8 ingredients, using hands. Transfer pork mixture to a lightly greased 8 1/2- x 4 1/2-inch loafpan.
2. Bake at 325° for 1 hour and 45 minutes to 2 hours or until a meat thermometer inserted in center registers 160°.
3. Prepare Gravy: Cook bacon slices in a large cast-iron skillet 8 to 10 minutes or until crisp; remove bacon, and drain on paper towels, reserving drippings in skillet. Increase heat to medium-high. Add tomatoes, cut sides down, and onion slices. Cook 6 to 7 minutes on each side or until charred. Remove from heat. Pulse tomatoes, onions, vinegar, and next 2 ingredients in a food processor just until coarsely chopped and combined. Stir in bacon.
4. Prepare Potatoes: Preheat broiler with oven rack placed in middle position. Bring Yukon gold potatoes, 1 Tbsp. sea salt, and water to cover to a boil in a large saucepan over medium-high heat; reduce heat to medium, and cook 15 minutes or until tender; drain. Combine potatoes, panko, and next 5 ingredients in a large bowl; mash with a potato masher to desired consistency.
5. Place 12 meatloaf slices on a lightly greased rack in a broiler pan. Spoon potato mixture generously over meatloaf. Broil 4 to 5 minutes or until potatoes are golden and crisp. Serve between bread slices with gravy.