Another option is to get a cabinet without USB 3 port and purchase a Cooler Master USB 3.0 Adapter which fits in a 5.25"/3.5" inch drive bay. This is available from SMC @600 bucks. Pair it with Gamma and you can actually save some bucks.
Other : Cooler Master USB 3.0 Adapter - Rs 600 with Free Shipping
dunno its available or not but corsair carbide 400r is best mid tower cabinet I have seen so far though it will be out of budget