Are you guys aware of any better datasets containing the location of commodity crops, such as corn and potato?
Have you looked at the SPAM data out of the International Food Policy Research Institute?
I don't know if you're looking for the same resolution as the CropScape data, but SPAM produces 5' estimates of physical area, harvested area, production and yield on 42 crops globally circa 2000 and 2005.
The UN COMTRADE database has extensive information relating to trade in commodities between countries.
This link is to World Bank's forecasts on commodity markets: