Amazon.com: TRENDnet Powerline 500 AV Nano Adapter Kit with Built-In Outlet, With Power Outlet Pass-Through, Includes 2 x TPL-407E Adapters, TPL-407E2K (Renewed)
WD-T1200 powerline adapter with passthrough - China Powerline Adapter, Powerline Ethernet Bridge | Made-in-China.com
networking - Does the current passing through a pass-through Powerline adapter affects its speed? - Super User