http://glutenfreegirl.blogspot.com/2010/02/gluten-free-crusty-boule.html
Since I'd run out of brown rice flour, I substituted 1/2c millet, 1/2c teff, and 1/4c sweet rice This, according to my math, added up to the same weight as 1c brown rice flour, though higher in protein. If you're a by-weight baker, the weights I used were: 158g brown rice (or my subs); 102g sorghum, 180g tapioca. I also left by bread to rise and rest longer than called for. These changes weren't willful; just the way it worked out. My bread turned very dense and moist with very small bubbles, a great crunchy crust (not super-thick) and wonderful sourdough-like flavor. I can only imagine the results if I would've followed directions ;)