I think I saw brown rice flour at an organic store once, or else Dragonbabe got it online. I'll try to check for you later. Meanwhile, what I recommend is first identifying the Chinese names, and then asking for them at organic shops like the Cottonfield chain.
Millet (and organic millet) are easy to find here; dunno about the flour offhand but if you got a small grain mill you could make some of these flours easily. I don't know how hard it is on a coffee grinder to put other grains through it.