Into a bowl sift together the flour, the baking powder, the baking soda, and the salt. In a large bowl with an electric mixer cream the butter with the sugars, beat in the vanilla, the eggs, 1 at a time, the zest, the banana, and the sour cream. Add the flour mixture, beat the batter until it is just combined, and stir in the macadamia nuts and the coconut. Divide the batter among 5 buttered and floured loaf pans, each 5 3/4 by 3 1/4 by 2 inches, and bake the breads in the middle of a preheated 350°F. oven for 35 to 40 minutes, or until a tester comes out clean. Remove the breads from the pans and let them cool, right sides up, on a rack. The breads keep, wrapped well in plastic wrap and foil, chilled for 1 week or frozen for 1 month.