LG has announced a Quad HD IPS display that is 538ppi.
At 5.5in, it's smaller than the Oculus Rift panel but gives 2560 x 1440 or what would be 1280 x 1440 per eye.
No idea how space-filling the pixels are, though.
And there's nothing to say the Rift would use something like this. But it's interesting to see where the technology is now at.