Combine first 4 ingredients in a large zip-top heavy-duty plastic bag; stir well. Add scallops to bag; seal bag, and marinate in refrigerator 30 minutes.
Bring wine to a simmer in a large nonstick skillet over medium heat. Add lettuce leaves; cover, reduce heat to low, and cook for 3 minutes or until lettuce wilts. Remove from heat; remove lettuce from skillet with a slotted spoon, reserving wine.
Spoon 1/2 cup scallop mixture onto center of each lettuce leaf. Fold in 4 sides of lettuce to cover scallop mixture, forming a packet.
Add clam juice, vinegar, and bay leaf to reserved wine in skillet, and bring to a boil. Carefully place each lettuce packet, seam side down, in the skillet. Cover, reduce heat, and simmer 5 minutes. Remove from heat; let stand, covered, 5 minutes. Remove packets with a slotted spoon, and place on individual serving plates. Discard bay leaf.
Bring cooking liquid to a boil over medium-high heat; cook 7 minutes or until reduced to 2 tablespoons. Remove from heat; scrape bottom of skillet with a wooden spoon to loosen browned bits. Gradually add yogurt to skillet, stirring with a wire whisk until smooth. Spoon 2 tablespoons sauce around each packet; top with 1 tablespoon bell pepper. Serve immediately.