To prepare soup, sort and wash beans, and place in a large Dutch oven. Cover with water to 2 inches above beans; cover and let stand 8 hours. Drain; return beans to pan. Add 6 cups water; bring to a boil. Reduce heat, and simmer for 45 minutes or until tender. Drain; return beans to pan.
Add leek and next 9 ingredients (through dash of thyme) to pan, stirring to combine. Add 10 cups water; bring to a boil. Reduce heat; simmer 30 minutes or until potato is tender.
Stir in zucchini, macaroni, and green beans; cook 15 minutes or until macaroni is tender. Discard bay leaf.
To prepare pistou, combine basil, cheese, and garlic in a food processor; process until a stiff paste forms. With processor on, slowly pour oil through food chute; process until well blended. Serve with soup. Garnish with thyme sprigs, if desired.