Samsung SPH-I800 may be the ATIV S variant for Sprint
Phone 8.But a tiny piece of this whole puzzle has apparently surfaced on the web. The Bluetooth SIG has certified a Samsung smartphone with a model name SPH-I800, which is clearly headed to Sprint. We know that since "SPH" is a model name prefix used by the carrier. And while the database entry does not specify what platform runs on the device, clues found online indicate that the smartphone is powered by Windows
Rumor has it that Sprint will be offering the Samsung ATIV S as one of its two first Windows Phone 8 smartphones, so that might be the device behind this mysterious model number. But whether that's really the case or not will be known after Sprint itself makes an official statement on the matter.