I recently found a recipe by JMonkey for Whole Wheat Buttermilk bread that he posted on July 10, 2006. A search of TFL will quickly locate the original post for you, and I would recommend that you read it. The bread he made was based on one of the recipes from Laurel's Kitchen Bread Book, but JMonkey did a comparison of baking it "straight" and baking with a biga. His success with the biga version inspired me to try it myself. I have had very little success with whole grain baking in the past. Most of my breads were much too heavy, and often had a slightly bitter taste.