Deepak, not sure if you found your orange Lumia 830 yet. I was facing the same problem - wanted an orange panel. Online stores were selling it a premium of INR 7k (roughly US$ 100 more) over black. Back in April, a friend of mine working in MS helped me get what the Nokia priority dealer said one of the last white 830 available in New Delhi. I also bought an orange panel (INR 1,500) and my orange beauty was ready.
The phone is great and camera is amazing. I would suggest you to go for black if you cannot find white/orange anywhere else. I had also thought of the same as a back up. But I agree the metal frame looks better in white/orange.
Question to everyone: Why is 830 thought as overpriced, especially if it is available at around INR 21k (~ US$ 330) ?