I don't know about 12" ear.  But Here something I don't remember seeing before.  5 ears on one stalk. Three that look like they might make a decent ear. Then the Tiller (as least I think It's a tiller) stalk is forming 2 ears.  One that might make a half an ear.  Yes this is along the edge of the field and there's about an 18" space on the near side and 24-30"  between plants.  

(5 Ears on 1 plant.jpg)

5 Ears on 1 plant.jpg (116KB - 40 downloads)