Seagate has announced a wireless / USB 3.0 hard drive with built-in battery
The GoFlex Satellite has 500 GB of storage, up to 5 hours of battery life and 25 hours of standby time.
Seagate says that the drive can support three simultaneous HD streams to devices via web browser or to iOS devices via a free app. An Android app is "expected to be available by this summer".
The drive uses Seagate's GoFlex architecture, which supports connection to USB 2.0, USB 3.0, eSATA and FireWire 800 hosts via swappable adapters. A USB 3.0 adapter is bundled with the drive along with Media Sync software for automatically loading media onto the drive from a host computer. Wireless connection is via a built-in 2.4 GHz band (802.11 b/g/n) radio.