The source is Digitimes. They report hundreds of plausible things, some based on things we know from other sources already (adding nothing) and some of which by luck turn out to be true. Few people bother to note all the times they're wrong, but their track record is poor.
I'm sure Digitimes loves the attention, but disregard this as pure speculation. Not a real "source."
As for retina, all of the following must be solved first:
* Bigger battery to drive that power-hungry display (remember: the iPad 4 is thicker and heavier than the iPad 2 for this reason!)
* Bigger battery to drive the powerful CPU and GPU needed to drive all those pixels.
* Making that extra-powerful battery happen without the device being thicker and heavier
* Fitting the thicker retina display in the same thin case... so maybe the battery has to be... smaller?
* Achieving high enough yields of the new display--and being confident of those yields (why make a better iPad if that means selling fewer?)
Those will be solved... but soon? I'm doubtful. Sounds like 2014 to me.
Apple stockholders are probably hoping you're wrong and we get a retina iPad mini this year. No retina on the mini will be seen as a FAIL by the media and many MacRumors readers. Wall St. will respond accordingly. Something other than a lackluster iPhone 5S update would also be appreciated.