I found the adapter for a power supply in the power port at seat 3F on a reconfigured S80. I think the plane's prior route included ATL as there was a Hertz road map in the magazine pocket.

The adapter is the 3" or 4" long piece that plugs into the power port.

After the thread about the iPod, I decided to try this different approach to lost items. In a week or so, I will take the adapter to the Dallas lost and found office if I am unsuccessful in locating the owner.