SamMobile published an image this afternoon that really kind of explains itself: this is, purportedly, the Galaxy S4 Zoom. The concept is obviously pretty simple - it's a Samsung smartphone with a big-ass camera mounted on the back. Don't get your hopes too far up on the smartphone aspect, though, as even SamMobile is tempering expectations on the specifications. Allegedly, the S4 Zoom will be packing a 4.3" qHD display, dual-core 1.6GHz processor (likely a Qualcomm chip), 8GB of internal storage (with microSD slot, of course), and Android 4.2.2.
So, essentially, this is more like a Galaxy S4 Mini that has had aforementioned freakishly large camera module attached to it.