To prepare the fennel gremolata, combine first 4 ingredients in a small bowl, and set aside.
To prepare beans, sort and wash dried beans; place in a large Dutch oven. Cover with water to 2 inches above beans; bring to a boil, and cook 2 minutes. Remove from heat; cover and let stand 1 hour. Drain beans.
Trim fat from lamb. Combine rosemary, 1/2 teaspoon salt, and 1/2 teaspoon pepper. Rub surface of lamb with rosemary mixture. Heat oil in a large Dutch oven over medium-high heat. Add lamb; cook 10 minutes, browning on all sides. Remove from pan. Add fennel bulb, carrot, fennel seeds, garlic, and leeks; cover, reduce heat, and cook 10 minutes, stirring frequently to deglaze pan. Stir in broth and wine, scraping pan to loosen browned bits. Return lamb to pan; add beans, 1 tablespoon fennel fronds, thyme, and tomatoes. Bring to a boil. Cover; reduce heat. Simmer for 1 hour and 15 minutes or until lamb is tender; discard thyme. Remove the lamb from pan; cover and keep warm.
Simmer the bean mixture, uncovered, 10 minutes. Sprinkle bean mixture with 1/8 teaspoon salt and 1/8 teaspoon pepper. Remove lamb from bones. Divide the lamb among 4 shallow bowls, and serve with bean mixture and fennel gremolata.