White Lumia 928 is back in stock at Amazon now and it has climbed up to the Amazon’s best seller list. Currently it is at 11th rank. In case you are surprised to White overtaking Black Lumia 928 in sales, then thing is Black Lumia 928 is still out of stock at Amazon. Both Radioshackwireless and Amazon which are selling Lumia 928 for only $49 on 2-year new contract are facing stock outs, it seems.
Thanks @easycapexpertti for the Tip. Cheers!!