JKurz1, I've been experimenting with making my own whole grain bread, so I have counts for the flours on a lot of these (just the flour, not anything else put into the bread). I'll give these in cup measurements since the bread will probably have at least 1 cup of a different flour (if multigrain, maybe only 1/3 a cup -- you try for a 3:1 ratio of wheat flour to others (because of gluten). I suppose they could add in wheat gluten and up the amount of the other flours ....
Spelt = 460 Cal, 4g Fat, 88g CHO, 8g fiber, 16g Protein
Oat 1 Cup = 303 Cal, 6g Fat, 48g CHO, 9g fiber, 12g Protein
Wheat Bran = 120 Cal, 2g Fat, 40g CHO, 24g Fiber, 8g Protein
Rye = 415 Cal, 3g Fat, 88g CHO, 29g Fiber, 18g Protein
Buckwheat = 402 Cal, 4g Fat, 85g CHO, 12G Fiber, 15g Protein
Steel Cut Oats = 560 Cal, 10g Fat, 108g CHO, 16g Fiber, 24g Protein
I don't have the GIs on these flours handy. Remember that what you get in 1 slice will be significantly less. You can figure on the 1/3 to 1 cup of a flour (other than wheat) per loaf, so divide by number of slices.
Thought this might help you decide on type of bread (if you want bread).