The thirty-fourth Bread Baker's Apprentice challenge (from the book by the same name authored by Peter Reinhart) is Pumpernickel Bread, and is found on pages 246-248.
Using the barm from the original sour dough I made for this section of the book (and by now with multiple dividings and feedings the barm smells sour and has a nice tang to it), I made a full portion of this bread, 2 bread pan loaves, as we wanted to use it for lunch sandwiches and that size fits well in a sandwich baggie. The rise was not as high as I had hoped (something in me loves a nice high loaf apparently and I am not getting it with these sourdough breads, probably because they aren't supposed to rise that high maybe?).
The ingredients: barm, coarse whole rye (pumpernickel) flour, water, bread flour, brown sugar, cocoa powder, instant yeast, bread crumbs, vegetable oil, and salt.
This is a two-day bread, one to make the soaker and firm starter, and the next day for the assembly, rising times, forming, and baking. The dough came together easily, I kneaded it by hand, as I most always do, and it came together in about 7 minutes of steady kneading. The rising times were about the same as suggested in the book, but I kept expecting more height, so I let the last rise go a little longer and when nothing more was happening, I baked the bread for the time stated (no real oven spring either), cooled it, and we used it for Ruben sandwiches which was very nice. 
The taste has that nice deep pumpernnickel rye taste and the texture was just the right amount of soft. Mark used the bread to make his lunch sandwiches today and Matt's going for another Ruben for lunch. Apparently the bread was a success in taste.
And, just in case you were wondering, the addition of that cocoa powder did not make the bread taste like chocolate at all...I tested it to see and I could not detect any chocolate taste. I figured you were wondering about that, so for all of you non-chocolate lovers out there, rest assured, you can't taste the cocoa in the final bread. We also could not detect too much of a sourdough flavor...a little, but not as much as we were hoping.
I am thinking sourdough breadmaking, all in all, maybe not be my best shot at success. My attempts have been nowhere near that San Francisco sourdough goodness that we long to taste this side of the Rockies.
You can visit the main group and marvel the breads. I'm getting there...Slow and Steady. Our next challenge: Sunflower Seed Rye, found on pages 249-251.