Preheat your oven to 350 Degrees. Grease & Flour a 9 X13 or 2 round cake pans. Combine chosen flavor of cake mix and chosen flavor of pudding in a large mixing bowl. Add eggs and oil, and beat for about 2 minutes. Add the lemon-lime soda and mix until well blended. Pour all into 9 X 13 pans, or split between 2 round pans. Bake for 35 minutes or until a toothpick comes out clean.
While cake is baking, in a saucepan, combine margarine/butter, sugar, pineapple, flour & eggs, and cook on low-medium heat until thick. Add coconut and blend well.
Spread icing over cake while still warm. For a two layer cake, double icing recipe to use as filling.
If anyone has tried this recipe or "specific" variation of it and have a picture they're willing to let me use, please send via private message on facebook.