Samsung Galaxy S4 I9507 with Snapdragon 600 found on GFXBench
One would think that after the LTE-A version powered by a Snapdragon 800 processor, there would be enough Samsung Galaxy S4 versions out there already, but apparently not as another version following the same model number naming convention has been spotted from the GFXBench site. Marked as the I9507 there isn't much information available for it apart from tech specs that state that it uses a Snapdragon 600 chipset with a 1.9GHz processor. It looks to be using the same Adreno 320 GPU as the Samsung Galaxy S4 I9505 but apart from the fact that it is running Android 4.2.2 there isn't any other information. There weren't any details like pricing or availability but it could be either a dual-SIM version of the I9505 or a rebadged I9505 tied to a specific provider. It could also be the still unrevealed Samsung Galaxy S4 Max but we'll find out pretty soon as Samsung usually announces as soon as they can.