There is an organization consisting of TV and display manufacturers such as LG, Samsung, and Sony that are pushing to standardize all connections over one cable. Imagine a world with no more HDMI, audio, power, or network cables cluttering up your audio/video installation, but instead, all of those signals and connections use just one cable. The organization is called the HD-BaseT Alliance, and I see their goal as very forward thinking and I imagine the market will embrace that solution. Their one cable to do it all is a standard Cat5e or Cat6 cable with RJ45 (8P8C) connectors, and one of the hurdles they have faced is sending enough wattage over a standard Cat5e or Cat6 cable to power a 40″ display.
Everyone has heard of Power over Ethernet, which allows approximately 15 watts to be sent over a Cat5e or Cat6 Ethernet connection. In 2009, the IEEE ratified a new specification called PoE+ (802.3at) which allows roughly 30 watts delivered over 2 pairs or roughly 60 watts delivered over 4 pairs. In comparison, a 40″ display might take around 70 watts, so the PoE specifications were not providing enough power for HD-BaseT’s purposes. In October of this year, the HD-BaseT organization added the “Power Over HD-BaseT” standard to their specification, allowing 100 watts over a standard Cat5e or Cat6 cable. This will (eventually) allow you to install a flat panel display and it would receive uncompressed HD video, audio, a network connection, and up to 100 watts of power all over 1 Cat5e or Cat6 cable!
If you are interested in the specifics, I recommend you read the Introduction to Power over HD-BaseT white paper, which as of November 2011 can be found here.