Bring 3 quarts water and salt to a boil in a Dutch oven; add orzo and saffron. Cook 7 minutes or just until tender; drain and keep warm.
Add 1 tablespoon olive oil to pan. Place pan over medium heat; add sausage. Cook 3 to 4 minutes or until browned, stirring occasionally. Remove sausage from pan, using a slotted spoon; set aside, and keep warm.
Heat remaining 1 tablespoon olive oil in pan over medium heat until hot. Add red bell pepper, onion, and garlic. Sauté 3 minutes. Stir in corn and next 5 ingredients. Add clams; cover and cook 5 minutes.
Stir in mussels and shrimp. Cover and cook 6 minutes or until clams and mussels open and shrimp turn pink. Discard clams or mussels that do not open. Return sausage to pan. Stir in orzo and 1/2 cup parsley; toss well. Transfer to a large platter; sprinkle with remaining parsley. Serve immediately.