Preheat oven to 350°F.
Heat olive oil in a large Dutch oven over medium heat, and saute bacon and onion for 12-15 minutes, until bacon is semi-crisp, and onion is browned. Add sausages and 1/2 of the garlic, and saute for 4 minutes, until slightly browned.
Add wine, and scrape up any bits stuck to the bottom of the pan. Add stock, tomato puree, turkey, beans, bay leaf and thyme. Taste, and adjust seasoning accordingly. Bake in the oven, uncovered, for 30 minutes, adding more stock, if necessary to keep moist.
Mix bread crumbs with remaining garlic, parsley, salt and pepper in a medium bowl. Toss with melted butter until moistened evenly, and sprinkle on top of cassoulet. Bake for another 20 minutes. Push down breadcrumbs so they are slightly moistened, and bake another 20 minutes, until top crisps.