Combine onion, leek, celery and 2 tablespoons oil in a large skillet. Cook over medium-high heat, stirring occasionally, until the vegetables soften and begin to brown, about 12 minutes.
Add garlic and the remaining 1 tablespoon oil to the skillet; cook until garlic is fragrant, about 1 to 2 minutes. Transfer the vegetable mixture to a plate to cool.
Combine vegetable mixture and pork, beef, soy sauce, Worchestershire, eggs, bread crumbs, pepper and salt in a large mixing bowl. Using your hands, mix gently but well.
Place about a 15-inch length of plastic wrap on a clean work surface. Break off a grapefruit-size piece of the meat mixture. Shape it into a log that resembles the body of a wine bottle, and place it toward one end of the plastic wrap. Roll the log in the plastic wrap, compacting meat and twisting the ends of the wrap. If needed, poke a few holes into the ends with a knife to release air pockets. Repeat with remaining meat mixture (will make 4 or 5 loaves), then refrigerate for at least 20 minutes or up to 8 hours.
Preheat the oven to 300 degrees. Place about 6 to 8 bacon slices side by side on parchment paper, slightly overlapping them. Remove the plastic wrap from one of the loaves and roll the loaf over the bacon, wrapping the bacon around the meat and releasing the bacon from the parchment paper. Repeat with the remaining loaves and bacon.
Place the bacon-wrapped loaves on a rimmed baking sheet.