Grits from any grocery store.. They're always made from corn.
You could buy brown rice syrup from lots of places. What homebrew places have you looked at? I might go to Barley's today will look. Otherwise they should have it at Famous Foods.
I was looking for the roasted buckwheat, and other special grains for adding to give it beer taste.
I have brown rice syrup, and sourgum syrup from Dans. I was at barleys getting flaked wheat on the weekend and didn't see flaked rice or corn. I get my corn polenta grits from Galloway's, cheapest price i have found is there.
I was more curious if people use a cereal rest to on the non-malted/modified grains, like brown rice or grits? My questions was worded poorly.