With a sharp knife, peel crust from bread; discard crust or make into bread crumbs for use in another recipe. Cut bread into 1-inch cubes; set aside.
In blender or food processor, fitted with a metal blade, combine half of the following ingredients: drink mix, pineapple juice, evaporated milk, cream of coconut, and banana slices. Process until puréed; pour purée into a 6-cup bowl.
Purée remaining ½ of liquid ingredients and banana slices as well as eggs and liqueur, if desired. Combine both purées; set aside.
Combine raisins and crushed pineapple (and the juice); set aside.
Place about 2/3 of bread cubes in slow cooker, sprinkle with ½ cup grated lemon peel and spread 1 cup of the raisin-pineapple mixture over bread in slow cooker. Top with remaining bread cubes, then with remaining ½ tsp. lemon peel and raisin-pineapple mixture. Pour puréed ingredients into slow cooker.
Cover and cook on low for 6 hours.
Spread pudding into 8 or 10 dessert dishes and serve hot.
