If you take non-Retina at four inches to mean half the iPhone 5’s resolution, that is 568x320. That’s a PPI of 162; the same pixel density as the iPhone 3GS (a device that is four years old).
When I first read Jeffries report, I thought it was ludicrous to say that Apple would sell such a low density screen nowadays. However, I then remembered that Apple released the iPad mini in October, a device that, conveniently, has a display with exactly 162 pixels per inch. So now it doesn’t seem so crazy.