> some don't eat New World foods because their ancestors come from Old World stock

Because every native american comes from "old world" stock, having only come to north and south america around the time of the neolithic revolution, all new world foods are potentially suspect regardless of your ancestry.

It may be fun to argue over minutiae, but as I'm sure someone else has already pointed out (I did not read the ongoing conversation due to time constraints), eating paleo just isn't that difficult.  Following Cordain or Audette or the Eades or Hoggan, you'll do very very well in comparison to the average non paleo eater.  

Jim