I see in the support page Google makes mention of IP based tuners and even USB ones? Im well aware HDHomeRun is a thing, but I'd rather not stream the TV if there's already a vz cable box sitting under it, and I could just replace it with a physically connected cable card and the Android TV. But, after some googling I haven't seen anything as such. I always thought the live channels app was simply a aggregator, and had no actual media capabilities, it simply integrated the streams from other things, but the way Google writes their article makes it sound like tuner + live channels = profit. So, do any such devices exist? I've got a Nexus player on the N beta, so thankfully it does have the new codecs.
Pretty much none exist in the way we want them to, android tuners exist By companies like hauppage(PCTV) and D-Link, but they are geared towards mobile.
Funny thing is though, the drivers are integrated into the apps, all they need to do is update their apps to support AndroidTV + live channels and they would sell those things like hotcakes.
I emailed D-Link about this 2 months ago, and they pretty much said they have given up supporting their android tuner altogether.