In a large mixing bowl, beat the egg, pumpkin and sugar. Then use a food processor to finely grate up the zucchini. Be sure to use a thin cloth or fine strainer to get as much water as possible out of the grated zucchini, and mix it in.Then add in the flour, baking soda, salt, cinnamon, nutmeg and allspice. Mixing until everything is combined.
To make the crumb topping... In a small bowl, combine the flour, oats, brown sugar, cinnamon and butter using a pastry cutter or fork, until the butter is mixed in well and it is a crumbly consistency.
Pour the bread batter into a greased/floured loaf pan and cover it well with the crumb topping.