it seems Bitmain is still trying to improve productivity, they will not  give commitment easily untill they can offer enough units and confirm shipping date.

you can follow  bitmain official news via bellow three ways:

facebook: https://www.facebook.com/pages/Bitmain/602849346422962
twitter: https://twitter.com/BITMAINtech
Taobao : http://item.taobao.com/item.htm?id=36044366308