ZTE Nubia Z7 and Huawei Ascend Mate which will have 6.3-inch and 6.1-inch of screen displays, respectively, will soon be released. Apparently, it is now the trend for larger, bigger, and "HD-er" screens to show which smartphones offer powerful and dominant features among the different models available in the market.
LG and Philips are currently developing their 5+ inches smartphones and possibly will release them in 2013. It could be their preparation for the upcoming rumours about a new Galaxy Note 3 which nobody knows yet when will it take everyone by surprise.
LG is known for their reputation for screen making and its technology. Their products are used by Apple and Samsung for smartphone devices. At the recent CES 2013, three new displays were shown ranging from 5.5-inch to 12.9 inch and the first likely to the 5.5 is the Lenovo K900.
For the LG smartphone line up, the upcoming device is the Optimus G2 which is powered by Qualcomm Snapdragon S4 Prime and comes with 5.5 inches of screen size too.