While donut sandwiches aren't new, they're more typically something you'd find at the county fair, or a few eateries here and there, rather than something offered at a national quick serve chain. Then again, recent years have seen national chains looking to generate buzz with items like KFC's Double Down and the more recent Crazy Cheesy Pizza at Pizza Hut.
Of course the bigger question is whether there's any plans for a national launch. I reached out to Dunkin' Donuts and the official line is: "Currently, Dunkin’ Donuts has no plans for a broader national launch of the breakfast sandwich." Still, you never know...