In a large bowl, stir together flour, sugar, baking soda, baking powder and salt. In another mixing bowl, combine eggs, bananas, oil, buttermilk and vanilla.
Add wet ingredients to flour mixture, stirring just until combined. Fold in nuts. Pour into a greased 9"x5"x3" loaf pan. Bake at 350° for approximately 1 hour or until it tests done.