The USB 3.0 Promoter Group has announced [pdf link] a new super-charged power delivery spec for USB 2.0 and 3.0 connections, which could deliver up to 100W to external peripherals. Intended to encourage the adoption of microUSB on more gadgets - which may previously have demanded greater power than the current USB Battery Charging Specification 1.2 allows for - the work-in-progress standard would also allow you to flip the direction of the charging without needing to swap the cables around.
Intended to co-exist with the current v1.2 specification, rather than replace it, the new standard boosts voltage and current values to cater to higher-draw devices. However, it also allows gadgets to negotiate both factors, so that low-power peripherals don't get overwhelmed by higher-rated ports.
In fact, the USB 3.0 Promoter group reckon the next step for the connection standard is powering your notebook with it, rather than using your notebook to recharge other devices. "Charging the battery of a notebook PC, or simply powering that notebook PC while actively using the USB data connection, would be possible" group chairman Brad Saunders suggestions. "Conceivably, a notebook PC could rely solely on a USB connection for its source of power."
The final details are expected to be ironed out in time for Q4 2011, though it's not clear when we might see high-power ports show up on notebooks and other devices.