What oils are suitable for Indian cooking (i.e. extended frying duration)?
Indian food is commonly cooked with ghee (clarified butter), for both religious and flavor reasons.  Where ghee is not used, coconut or refined palm oil are common.  

I can also tell you from experience that Indian food can be made with unflavored vegetable oils (canola, sunflower or soy), without a deleterious effect on flavor or texture.