I've been on the mailing list for this working group for about a year now (I am an IEEE-SA member but you don't have to be to be on a WG), and one of the first things I brought up is my tendency to drop my electronics :)
A bit more detail, the current thinking is that it will use CAN 2.0 for the link layer but the physical layer is still being hashed out. The device needs communication to negotiate between the power adapter and the device to be powered. The device and power supply will communicate things like if it sourcing or sinking current (or capable of doing both), whether it is a battery, an intermittent supply like wind or solar, etc.
It sounds pretty cool if manufacturers go along with it.