Its grown in Kansas, and probably other states in this area as well. I think we use it for feeding cattle, pigs, etc. I have found Milo in mexican grocery stores in Chicago -the label says 'product of Jamaica' but it tastes the same as the aussie stuff. Most sorghum grown in the states is feed grain for animal consumption, and is high in tannic acid. The standard American Chocolate is like sweetenned wax.
White chocolate is almost impossible to find in most supermarkets.
If you're here for any length of time you'll start having dreams involving cherry-ripe's and violet crumbles. Ghiradelli has recently been acquired by Lindt. While probably regional, grocery stores carry Promised Land Dairy Milk which comes in plain, strawberry, peach, banana, coffee bean, vanilla, cherry, rasberry, eggnog, chocolate, and hazelnut. For this reason American producers often use cheaper substitutes that are not used in other parts of the world. For example, American soft drink manufacturers will often use corn syrup as a sweetener instead of the more expensive sugar, which is sold in America for much more than in other parts of the world.