As far as I can see from their Chinese website, official direct sales are all online (and it has not yet been released and is still in the preorder phase). You might wish to ask a local friend to order one for you.

Otherwise, poking around the electronics markets at Zhongguancun should prove fruitful, though you may end up paying more than retail if supplies are still constrained. Remember to compare prices and negotiate (discounts, free accessories, etc.) when dealing with these guys, and always make sure to test the device before walking off.