It seems like 2016 is primed to be the year for 4K to start making a splash. Sure, the TV sets have been available for a couple years now, but there's been very little content to go with it. Of course with Netflix, Amazon Prime and others dabbling with 4K, it seems like it's only a matter of time before Google Play does as well. The only issue with that though is that they currently have no first party devices capable of playing HEVC content on your TV.
Obviously, the Nvidia Shield is already capable of HEVC decoding, and is able to take advantage of Netflix's 4K offerings, but the device is still a little on the pricy side, and likely offers features that the average media junky isn't interested in, most notably the gaming. It seems like the market is ripe for an Android TV device that is $99-$125 that is capable of handling 4K, and the Nexus Player seems like the obvious choice to scratch that itch. Do you think we'll see something announced soon, or do you think Google is going to let someone else take a crack at it?
My guess is a 2 year release cycle, same as chromecast.
Fall 2016 - Nexus Player v2
Fall 2017 - Chromecast v3
Keep in mind, Nexus devices are rarely designed to make a profit. They are meant to encourage development and growth within the ecosystem and showcase new features. Sort of a baseline for OEMs to use. The Nexus 6P however, has been an exception to this model.