Heat gas or charcoal grill. In medium nonmetal bowl or large resealable food-storage plastic bag, mix lemon juice, ground red pepper and garlic powder. Add shrimp and scallops; stir or turn bag to coat. Cover dish or seal bag; let stand at room temperature to marinate while cooking bacon.
Meanwhile, in 10-inch skillet, cook bacon over medium heat 4 to 5 minutes, turning once, until lightly browned but not crisp (bacon needs to be pliable to wrap around seafood). Drain on paper towels.
Drain shrimp and scallops; discard marinade. Wrap 1 piece of bacon around each shrimp and each scallop half. Onto 6 (12- to 14-inch) metal skewers, alternately loosely thread shrimp, scallops and lemon wedges.
When grill is heated, place kabobs on gas grill over medium heat or on charcoal grill over medium coals; cover grill. Cook 4 to 7 minutes, turning once, until shrimp turn pink, scallops turn opaque and bacon is browned and crisp. To serve, squeeze juice from lemon wedges over shrimp and scallops.