Soak wood chips in water for 30 minutes; drain well.
Preheat grill to medium-high heat.
Place wood chips on hot coals. Place a large Dutch oven on grill rack. Close grill lid; heat 2 minutes. Add oil to pan; swirl to coat. Add shallots and garlic to pan; sauté 2 minutes, stirring frequently. Add tomato; close grill lid, and cook 3 minutes. Remove grill lid. Add wine; bring to a boil. Cook 5 minutes or until reduced to 2 tablespoons, stirring occasionally. Add thyme, juice, and clams; close grill lid, and cook 5 minutes. Remove grill lid. Stir in mussels; close grill lid, and cook 5 minutes. Coat bread slices with cooking spray; grill 1 minute on each side or until toasted.
Remove clams and mussels from pan using a slotted spoon, reserving cooking liquid in pan; discard any unopened shells. Cover clams and mussels; keep warm. Discard thyme sprigs. Bring reserved cooking liquid to a boil. Cook 15 minutes or until reduced to 3/4 cup; remove from heat. Add butter, parsley, and chopped thyme, stirring until smooth. Return mussels and clams to pan; toss to coat. Serve with grilled bread.