Yeah, Google has never made its own Nexus. However, Google HAS made their own Pixel, and a Pixel phone would certainly not be inconceivable. And just speaking for myself, a true, 100% 1st party device is something I'd be VERY excited to see.
However, none of the rumors I've read seem to mention anything about Pixel and the line between the two brand names seems pretty fixed. So I don't think we'll be seeing a Pixel Phone this year, unfortunately.
Which brings me to the Samsung rumor: I don't believe it. The suspicious timing, the very amateur look of the android nerds thing, and the fact that in what little googling I've done on the matter the Internet seems to be completely mum on any Samsung/Nexus business this year all leads me to suspect that we've been "April Fooled".
Cheers!