In a medium bowl dissolve gelatin in the boiling water. Remove 1 cup of the gelatin mixture and let stand at room temperature. Pour remaining gelatin into blender. Add mayonnaise, cream cheese, and lemonade concentrate to blender; cover and blend just until smooth. Transfer to a large bowl. Chill about 1-1/2 hours or until partially set (consistency of unbeaten egg whites), stirring occasionally.
Pour gelatin-mayonnaise mixture into a 9-inch springform pan or 9-inch round cake pan with a removable bottom. Chill for 30 to 45 minutes or until almost firm.
Arrange strawberries and banana on top of mixture in pan. Chill reserved gelatin until slightly thickened. Spoon over fruits to glaze. Cover and chill about 6 hours or until set. Makes 8 servings.