Rumors have circulated of an NVIDIA-designed Android tablet, but there has been little hard evidence of its existence. Thankfully, NVIDIA just provided some clues of its own: as Blog of Mobile noticed, the company recently sent a self-branded P1640 tablet to Taiwan's National Communications Commission for approval. While the filing reveals few details of the hardware apart from the expected presences of Bluetooth and 802.11n WiFi, it's safe to presume that the slate uses an NVIDIA-made processor like the Tegra 4. The real mystery is the P1640's intended audience. When NVIDIA already has a Tegra 4 reference tablet, the new design isn't necessarily built for internal use; it could also be a developer device or a consumer product like Shield. It's not clear if or when NVIDIA will announce the tablet, but you can check out a second NCC photo of the gadget after the break.