The LG Optimus G Nexus does exist, first hands-on account is here: Source

We are just into the fifth day of October and its already flooding with news and rumours related to the next Nexus smartphone(s).


And in today’s dose of the coverage, Android & Me was sent in, what is supposedly the first hands-on report of the LG branded Optimus G Nexus.

Yes, the insider who is said to have seen and even used the device says that there is indeed a Nexus branded smartphone that LG is working on called the Optimus G Nexus and looks similar to the Galaxy Nexus with a silver ring around its outer edge, like the iPhone 3G.
Moreover, the source has said that the device he used was running on Android 4.2 but it looks exactly like the Android 4.1.1 but is much fluidic and smooth.
The person who used the device said:
I can confirm the next nexus is LG Optimus based. The phone looks surprisingly like the Galaxy Nexus and does not have sharp corners like the LG Optimus we already know. It has a silver’ring like the iPhone 3G around the outer edge of the screen which seemed to be similar to the Galaxy Nexus in size but was much better in brightness.
I couldn’t have said if it was larger in the few minutes that I had the phone. Also, it has Nexus written on the back like the Nexus 7 except there is a color element to it. The ‘X’ is in four colors. There was also the LG logo on the back.
Android 4.2 in its current state looked exactly like the 4.1.1 we love. There were no tabs on that build version for home-screens as you suggested from your other tipster. What I was amazed by is how fluid everything seemed to be from exiting apps, switching, etc. It seems like they’ve increased the number of transitions and their types. It still had the hodge-podge mess of multiple communication tools: Messenger, GTalk, Voice and SMS. 
So with this, the rumours of LG Optimus G Nexus being into existence have only strengthened and if we are lucky enough, we could see the announcement of the smartphone by October-end or early November.