Prepare the Marinara Sauce; In a large saucepan, heat oil over medium heat. Add onions and garlic, sautéing until onions soften and garlic browns, about 5 minutes. Stir in tomatoes, white wine, and butter. Add meatballs to pot, and season with salt and pepper. Stir in parsley and basil; simmer for 1 hour.
Meanwhile, in a 20-quart stockpot, bring 12 quarts water to a boil; add salt. Slowly add cornmeal a handful at a time, stirring constantly with a large wooden stick or spoon to prevent lumps. Cook until polenta has thickened and just begins to cling to the stick, about 45 minutes. Remove from heat.
On a large (at least 72 inches-by-40-inches) clean wooden table or counter, carefully pour out polenta, rolling it out with the stick to smooth. Polenta should be about 1 1/2-inch thick.
Pour marinara sauce and meatballs over polenta. Sprinkle evenly with cheese; serve immediately.