http://www.mobilemarketer.com/cms/news/research/17101.html
The article refers to “Responsive Delivery” which is a term I hadn’t heard before. It seems to be a concept where you still send CSS/HTML/JS to all devices, but you change what resources/components you send based on the device.
I’m not sure how this would be easier than RWD, but maybe with some specific tools it is.