Preheat oven to 400 degrees F. Prepare Multi-Grain Medley according to package directions. Coat a loaf pan with non-stick cooking spray.
In a large bowl whisk together eggs, sugar and banana. Stir in rice, oil, milk, vanilla, zucchini (should be about 1 1/2 cups of grated zucchini) and walnuts. Add baking mix and stir just until all ingredients are combined. Pour mixture into prepared pan.
Bake 45 minutes, or until toothpick inserted in center comes out clean.
Cool 10 minutes then remove from pan and cool on rack.