Bring 10 cups water to a boil in a Dutch oven over high heat; add crab boil, potatoes, and sausage; return to a boil, and cook 10 minutes. Add corn, and return to a boil. Cook 3 minutes or until potatoes are tender. Add shrimp; cover, remove from heat, and let stand 5 minutes or just until shrimp turn pink.
Meanwhile, whisk together lemon juice and next 7 ingredients in a medium bowl.
Drain shrimp mixture. Cut kernels from cobs. Discard cobs. Stir together corn kernels, shrimp mixture, and lemon juice mixture in a large bowl. Serve immediately, or cover and chill up to 24 hours.