My son has solved the issue with Nabisco 100% Bran. You can't buy it any more, but Kellogg's All Bran "Bran Buds" are the replacement. Here is the muffin recipe using the two cereals. The recipe was cut down from 6 doz. to 3 doz.

BRAN MUFFINS
(Nabisco 100% Bran Muffins with bran substitute)
Makes 3 dozen

2 cups Kellogg's All Bran "Original"

1 cup Kellogg's All Bran "Bran Buds"
(Nabisco 100% Bran was bought by Kraft Foods, so the box was re-labeled Post 100% Bran, the product was discontinued June of 2006, which Shane W. confirmed by calling and emailing Kraft on 10/2/08)
(Suitable Substitute is Kellogg's All Bran Bran Buds)

1 cup boiling water
2 cups buttermilk
1/2 cup butter
2 eggs
2 1/2 cups flour
1 1/2 cups sugar
1/2 teaspoons salt
2 1/2 teaspoons baking soda

Pre-heat oven to 375 degrees F.

Measure the cereal into a medium mixing bowl. Pour boiling water over the cereal, add buttermilk. Let cool a few minutes.

Cream the butter and sugar together and beat eggs in one at a time. Add to the cooled cereal mixture.

Sift the flour with the baking soda and salt and stir into the cereal/sugar mixture only to dampen. Spoon into greased or paper-lined muffin tins until 1/2 full.

Bake for 15 to 20 minutes at 375 degrees F.

Store remaining batter in the refrigerator for up to one week.