Dissolve yeast in 1/2 cup warm water. Stir in whole wheat flour, 1 3/4 cups warm water, carrots, bananas, butter, agave, salt and cinnamon; beat until smooth using an electric mixer. Mix in enough flour to make a soft dough. Knead about 10 minutes, or until smooth and elastic, on a lightly floured board. Place in a large greased bowl and turn to grease all sides. Cover bowl and set in warm place to rise about 1 hour or until doubled in size. Punch down dough, divide in half, flatten each half with a rolling pin, or your hand, to 18 x 9-inches; overlap the two sides and fold into thirds. Roll each half up tightly and place in two greased 9 x 5 x 3-inch pans. Brush tops with melted butter. Let rise about one hour or until doubled in size. Bake at 375°F for 40 to 45 minutes or until crust is brown. Remove from pans and cool on wire racks.