According to China web site weibo where you can see a Lenovo banner announcement (picture above) of the Lenovo Vibe Z2 Pro of K920 will be real in August 5, 2014 and the specifications are:
The Lenovo Vibe Z2 Pro of K920 will feature a large 6-inch QHD (1440x2560 pixel) display. It will pack a 2.5GHz quad-core Qualcomm Snapdragon 801 processor coupled with 3GB of RAM. Front camera on the device will be 16-megapixel with dual-LED flash and optical image stabilization, while secondary front facing camera will be 5-megapixel.
Internal storage on the device is listed for 32GB, but Wei didn't mention any microSD card expandability. The Lenovo K920 is also said to come with 4G LTE support. The large screen smartphone will have a massive 4000mAh battery, and measures 156x81.3x7.7mm.