In a double boiler over medium heat, cook and stir eggs, sugar and vinegar until mixture is thickened and reaches 160 degrees C, remove from the heat; stir in butter. Cool.
In a large serving bowl, combine grapes, marshmallows, pineapple, oranges and bananas; add cooled dressing and stir to coat. Refrigerate for 4 hours or overnight. Just before serving, fold in whipped cream and pecans.