I'd be highly skeptical of a corn "purification" process. Being celiac and corn allergic, I've never heard of such a thing - it'd be great if it existed! I've found that there is a lot of misunderstanding among manufacturers about whether or not corn is left after processing. For some reason, it seems to be a common thought that it gets "processed" out. Where does it go?! Trust me - when I react to one of these products I know it hasn't gone anywhere. Also, Namaste has had some problems in the past as to where they have their corn test done. See this post about what one major food testing site says about corn testing: http://cornfreedom.com/blog/?p=131
I've had good luck with using 1T ground flax in 3T water, microwave for 30 seconds in quick breads, but haven't found anything that works in gluten-free, corn free sandwich type breads. I think it's the holy grail!