I'm not sure the hulls matter. If you can get a small quantity of hulled, try malting it, see what happens. Also, by the time it's been soaked and rinsed a few times in the malting, then roasted, I'd be surprised if any cross-contamination was still left.
I'm just starting experimenting with millet, and I'm getting it in 2kilo bags from an Asian grocery (if I have the conversion right, about 50cents/pound). We have loads of them in England, dunno if you do in Oregon.
If I wanted to do large amounts though, I'd maybe be looking at petfood suppliers: it's used for feed for birds.