The SM-T800 seems to be the Wi-Fi-only version of the Samsung SM-T801 and SM-T805, both of which appeared at the FCC at the end of last month.
The Samsung SM-T800 was previously spotted in a benchmark test which suggested that its features included: a 1.9GHz Exynos 5 Octa processor, 3GB of RAM, 16GB of internal memory, 8MP rear camera, and a 2MP front-facing camera. The tablet allegedly sports a 10.5-inch display with 2560 x 1600 pixels, and runs Android 4.4.2 KitKat.
The could be variants of that rumored 10.5-inch Samsung AMOLED tablet that we first heard about in December. This, however, is just a guess for now.
Earlier today, Samsung announced three new Galaxy Tab 4 slates, all aimed at customers looking for affordable devices. The SM-T800, SM-T801 and SM-T805 will definitely not be affordable - not if they have AMOLED screens, and the specs listed above.