Depends on where you are. There are manufacturers who sell the stuff to foodservice, but they may be regional if not more local. Have you tried looking in the phone book/Googling for Indian food manufacturers?
Or you could just buy a zillion cans/jars of Patak's, which I think is available all over the place. I know they do retail sizes, not sure if they do industrial.
Depends what you are expecting. Korma is derived from the Hindi word meaning 'braised' so the sauce you use to braise whatever it is you are cooking could be anything.
Unfortunately, westernized Indian restaurants have this 'code' whereby korma means mild and creamy with nuts (usually almonds or cashews). If this is what you are looking for then you it is easy to get commercially from the internet.
It is relatively easy to make and I have a Chicken Korma recipe on my site