Western Digital has announced a 7 milimeter thin 5400 RPM hard disk. The Scorpion Blue is targeted at laptops and due the thinness the HDD seems to be targeted for usage in Ultrabooks. The HDD has a 2.5"' formfactor but also fits in 9.5mm bays of regular laptops and comes in the sizes 320 and 500 GB.
The HDD contains a single platter and makes use of 8MB of cache. The MSRP for the 500 GB, model #: WD5000LPVT is $99.99 USD and the 320 GB, model #: WD3200LPVT is $79.99 USD and come with a two year limited warranty. It supports various WD technologies such as SecurePark, ShockGuard and WhisperDrive.