According to a supposedly confirmed report from the Wall Street Journal, the LG G2 which will soon be unveiled at LG's August 7th press event, does indeed have 5.2-inch display as was rumored previously. Here's a quote with some additional info,

LG’s invitation to the Aug. 7 event shows a picture of a black satin box with a phone-shaped indentation and the text “Great 2 Have You,” possibly a play on the name of the new Optimus G model. People familiar with the matter said the phone will likely be called Optimus G 2.

The new phone to be released next month will have a 5.2-inch screen, said one person familiar with the matter. The current Optimus G model has a 4.7-inch display.

LG Display Co. 034220.SE +0.54%, which supplies screens for LG’s phones, issued a statement shortly after the invitation was sent out, announcing its new liquid-crystal-display screen of 5.2 inches. The company said the screen is only 2.2 millimeters thin–the slimmest full high-definition screen available–and that it also comes with the narrowest bezel of 2.3 millimeters, giving it a sleek build.
The new G2 flagship from LG is shaping up to be a serious contender in the high-end smartphone market. If LG can start improving the rate at which they update their devices, they could get really competitive with Samsung and Apple.

Source: WSJ