In a large bowl, mix together flour, baking soda, baking powder, salt and sugar.  In a separate bowl cream together butter & eggs.  Add the nuts and / or dates to the dry ingredients.  Mix well to coat.  Add the butter and egg mixture to the dry ingredients.  Lastly add the mashed bananas.  Mix well until all the ingredients are well combined.  Spoon batter into a greased loaf pan.

Bake at 350 degrees for 1 hour.