Samsung's S5 LTE-A is a GS5 variant with upgraded hardware, most noticeably a 5.1" QHD (2560x1440, 577 PPI) Super AMOLED display and LTE-Advanced (which supports speed up to 225 Mb/s!). It's also the world's first phone with Qualcomm's Snapdragon 805 (2.5Ghz). Other features include 3GB RAM, 4K video playback, Android 4.4, 16 MP rear camera, 2,800 mAh battery, heart rate sensor and a fingerprint scanner. Like the GS5, this phone is waterproof and dustproof.
The S5 LTE-A will be released in Korea (via SK Telecom) in the summer of 2014 for about $920. It will probably not be available elsewhere.
QHD (2560×1440) Super AMOLED