With a sharp knife, peel crust from bread; discard crust or make into bread crumbs for use in another recipe. Cut bread into 3 cm 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 pureed; pour puree into a 6 cup bowl. Puree remaining half of liquid ingredients and banana slices as well as eggs and liqueur, if desired. Combine both purees; set aside. Combine raisins and crushed pineapple (and the juice); set aside. Place about two third of bread cubes in slow cooker, sprinkle with half tsp 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 half tsp lemon peel and raisin-pineapple mixture. Pour pureed ingredients into slow cooker.
Cover and cook on low 6 hours. Spread pudding into 8 or 10 dessert dishes and serve hot. Garnish with fresh mint sprigs.