Contrary to rumors from the rumor mill, at least one analyst believes that the next-gen iPad mini will not feature a Retina display. He believes that the Retina-equipped iPad mini will be coming sometime in 2014. The analyst in question is Richard Shim from NPD DisplaySearch.
Taking a critical eye towards his predictions, a few problems appear. Since we're already in the second part of 2013, it seems unlikely that Apple would launch a major upgrade to the iPad mini in early 2014 as predicted. It also seems like a large oversight for Apple to neglect the iPad mini.
We'll see sometime in the fall whether or not Apple will be equipping the iPad mini with a Retina display. As always, take this with a grain of salt.