Hi bjplayer,as George has said what you are calling 'stock' is what most on here refer to as either Base Gravy or Base Sauce , the root Vegetables you refer to would be Onions ,Carrot,plus usually Capsicum Pepper,Tomato,Garlic/Ginger and various Spices.
It does sound a lot of work if it's the first time you've made a Base Sauce but I've made up to 9 litres in one go and that will last for weeks frozen in T/A containers in the freezer.
If you don't fancy making a Base Sauce you could look at the ' Curries from Scratch ' recipes on the Forum.