In a heavy saucepan over medium heat, combine sugar, flour, salt, milk and evaporated milk. Cook, stirring, until bubbles form at edges and mixture is slightly thickened. Slowly pour a small amount of hot milk into the beaten eggs, stirring to combine. Then remove milk mixture from heat and stir the eggs into the milk until fully incorporated.
Stir in vanilla, chocolate milk, strawberries, bananas and pureed pineapple with its juice. Pour into the freezer canister of an ice cream maker, adding milk as needed to bring to fill line. Chill in refrigerator until quite cold, then freeze according to manufacturer's instructions.