In a large mixing bowl stir together flour, sugar, baking powder, orange peel, baking soda, and salt.
In another mixing bowl stir together eggs, 1/2 cup of the thawed orange juice concentrate, the oil, and 1-1/2 cups water.
Add to flour mixture. Stir by hand just until combined. Fold in dates and nuts.
Divide mixture evenly between two greased 8"x4"x2" loaf pans. Bake in a 350 degree oven for 50 to 55 minutes or until a toothpick inserted near the centers comes out clean. (Or, divide mixture evenly among four 5-1/2"x3"x2" loaf pans and bake for 40 to 45 minutes or until loaves test done.).
Cool in pans for 10 minutes; remove from pans.
Generously brush tops and sides of loaves with remaining orange juice concentrate. Cool thoroughly on wire racks.