Launching with iOS 8.1.
Some Apple Retail Stores Offering 30-Day Window to Exchange iPads for New Model
The manager at the Stockton Street store in San Francisco explained that "this specific store" would allow purchasers of the third-generation iPad to exchange their device for the fourth-generation iPad if purchased within the last 30 days. She emphasized that, unless the recently-purchased iPad showed serious signs of wear-and-tear, the usual 14-day return policy would be waived.
"And what about other stores?" You'll have to call and find out. She explained, "We can't speak to other stores' policies -- this is something our store has decided to do."
The report suggests that the extended return window is not an official company policy and thus customers may find spotty adherence to it, but stores generally have some flexibility in allowing returns considering certain circumstances, and with any luck some recent iPad customers may find themselves able to upgrade to the latest model without penalty.