Place millet in a small bowl; cover with 3/4 cup hot tap water. Set aside until millet softens and absorbs water, about 15 minutes. In a small bowl or cup dissolve yeast and honey (if desired) in 1 1/3 cups warm water; set aside until foamy.
In a large bowl, combine flours and salt. Add yeast mixture; knead until mixture is incorporated, about 2 minutes. Drain millet and add to dough. Knead about 10 minutes, until millet is evenly incorporated (dough will be somewhat sticky).
Lightly oil large bowl. Place dough in bowl, immediately turn dough over so that oiled side is up. Cover with a damp towel and let rise until doubled in bulk, 2 to 3 hours.
Punch down dough; shape into a round loaf. Place loaf on a floured peel or baking sheet. Sprinkle oats on top, pressing down lightly to stick to dough. Let rise until almost doubled in bulk, about 1 hour.
Place bread-baking tiles or baking sheet into oven, preheat to 450 degree F. Slash top of loaf decoratively and slide onto heated tiles or baking sheet. Bake until top is well browned and bread sounds hollow when tapped on bottom, 30 to 45 minutes.