The original NVIDIA SHIELD (before the Tablet or the set-top box, so just called "SHIELD" at the time) was a surprise revelation at CES 2013. This high-powered Android device with an Xbox-style controller and a flip-up screen was unlike anything we had seen before, and though it never became a runaway hit, many (including yours truly) have been hoping that NVIDIA would update the design in addition to its more conventional SHIELD entries. Get your thumbs ready: it looks like a SHIELD 2 is being certified by both the Wi-Fi and Bluetooth trade groups.
Chinese Android news site Juggly spotted a new entry for a device called the "SHIELD Portable" on the Bluetooth Special Interest Group certification listing, published on March 15th. The SHIELD Portable P2523 is listed right next to the SHIELD Console P2571, implying (but not guaranteeing) that both gadgets are using the same Tegra X1-powered system-on-a-chip. Other than that, and of course the presence of Bluetooth, there's nothing else to be gleaned from the SIG listing.
After seeing Juggly's report, Liliputing also spotted a new SHIELD Portable on the Wi-Fi Alliance certification site. The device has the same model number, P2523, and it's noted as running "Android version 5" (the original SHIELD Portable is still on KitKat). In addition to 2.4GHz and 5GHz Wi-Fi capability, it will be able to use A, B, G, N, and AC bands - the original SHIELD was not equipped with AC Wi-Fi.
That's about it for now. The original SHIELD and SHIELD Tablet were released in the summer in the northern hemisphere, and the set-top box will be available in May. I'd expect a new Portable sometime in July or August, if indeed it's coming - on occasion we've seen gadgets get certified without ever hitting the market.