A few drawbacks with large capacity external desktop drives include their size, weight and use of a bulky power supply.  2.5" external drives on the other hand are usually limited to USB connectivity and have a much more limited capacity.  LaCie has now released Little Big Disk, which offers the performance of two drives in RAID 0, while still fitting in the palm of your hand and running without a separate power source.

LaCie's Little Big Disk Quadra features a capacity of 1TB, using two 5400rpm 2.5" HDDs in a RAID 0 configuration.  Its connectivity includes eSATA and FireWire 800 with burst transfer rates of 110MB/s and 80MB/s respectively.  The drive is fully bus-powered using the FireWire interface.  It includes an adapter for FireWire 400 connectivity and a second FireWire port to allow daisy-chaining.  By using 2.5" disks, the drive is 60% lighter than typical desktop drives, weighing just 1.4lbs (650g).  The drive is fully play and play with Windows Vista and Mac OS X 1.05 Leopard. 

Going by the LaCie website, the Little Big Disk Quadra is silent and fanless, includes USB2.0 support, comes bundled with eSATA, USB and FireWire cables and Windows and Mac backup software, has a 3-year warranty and has a retail price of $699.99. 

Full specifications can be accessed on the LaCie website product page.