I think the MiBox is the new Nexus Player. If there were a new Nexus Player in the works, I think it would have been announced during Google IO which just ended.
I'm hoping for a new model, but I would like to point out that this isn't the first time the Nexus Player has been removed from being listed.
I am fine with this as long as the device is still supported in the sense that it receives is updates. If another device replaces it, it could even breathe new life into the platform. I just hope it's not going to be forgotten when updates occur :(
Maybe they will release a new Nexus Player along with the phones toward the end of the year. Seems odd that they would discontinue it before having a replacement though.
Is this the new Nexus Player? http://www.androidpolice.com/2016/05/24/google-is-preparing-to-add-the-raspberry-pi-3-to-aosp-it-will-apparently-become-an-officially-supported-device/
Sadly, I would bet it will just be a standard AOSP builds, not Android TV.
As many of us suspecting, the Nexus Player seems to have been discontinued. Just a reminder though, discontinued does not mean end of life. The Nexus Player has a dev preview available for Android N and will presumably get said update come fall.
Hopefully we will also see a refresh of the device line; it would follow suit with the Chromecast (2 year device release cycle), though I don't remember the Chromecast being pulled from the store prior to the CC2 release.