Kathy, I don't know where you can buy bulk ABM Bread mix,, but this is a tried and true recipe.

Bread Machine Mix
Makes 5 1/2 quarts (22 cups) of mix

Combine the following ingredients to make your mix:
20 cups of flour* (5 lbs)
1 cup sugar or brown sugar
1 heaping tablespoon salt
1 cup powdered buttermilk or instant nonfat dried milk

Combine ingredients thoroughly and store in an air-tight container in a cool place. Use within 6 to 8 months.

Basic White Bread
Makes one large 1 1/2 pound loaf

Put into your bread machine in order:
1 cup warm water
1 egg**, beaten, room temperature
2 tablespoons butter or cooking oil
3 1/2 cups bread mix, room temperature
1 1/2 teaspoons active dry yeast***

Bake on short cycle.

* Any combination of flours can be used, replacing up to half of the flour (10 cups) with a whole grain flour. For EACH CUP of whole grain flour used, add 1 tablespoon of vital wheat gluten to the mix.
** Substitute powdered egg for a fresh egg if you are going to be baking the bread on a timer.
*** Another version of this recipe calls for 1 tablespoon yeast. - ed.

Mix may be used to make pizza dough, calzones, cinnamon rolls or dinner rolls. Remove dough at the end of the first kneading/rise cycle and finish by hand.

Source: Deb Vaughn