When wireless technologies aren't an option new technologies that reduce the number of wires needed are the only option. Most electronics need a constant supply of electricity so adding more features to power lines is pretty logical. The unfortunate thing about doing that is it usually requires conversion boxes. This can complicate things but for older homes it's usually a much more attractive option than blowing holes in the wall.
NETWORKING TECHNOLOGIES
Ethernet over Power
Ethernet over USB
HDMI over Coaxial
POWER TECHNOLOGIES
Power over Ethernet
Powered USB
Power over eSATA
