Apple recently filed a patent for a product described as "Magnetic Connector with Optical Signal Path." The patent filing describes a MagSafe-style cable that would provide both data and power to a device. The power cable would connect magnetically and contain additional internal pins allowing for the transmission of data as well as audio and video signals. Downstream, the cable would include the appropriate adapters for each device you want to connect.
This patent sounds very similar to HDBaseT, a cabling system proposed by Samsung Electronics, Sony Pictures Entertainment, LG Electronics and Valens Semiconductor. This technology uses an RJ-45 cable to transmit data via a 100BaseT connection, HD video, audio and power. The specification was finalized in June 2010, and products using this technology may debut in 2011.
Another similar competing technology, LightPeak, is being developed by Intel. The optical cable technology would be a single cable replacement for SCSI, SATA, USB, FireWire, PCI Express and possibly power and display connections as well. Apple is reportedly interested in this technology and was rumored, at one point, to be incorporating it into its MacBook Pro lineup.