Trans International has released the Pro Drive
(http://www.transintl.com/store/category.cfm?Category=2746&RequestTimeOut=500),
a storage enhancement solution for the Mac Pro. Pro Drive enclosures
are designed to enhance the performance of Mac Pro internal drives.

Pro Drive is a dual drive RAID enclosure accommodates up to two
2.5-inch SATA hard drives. It can be used as redundant drive to
protect against drive failure (RAID1) or Striped to become one high
performance drive (RAID 0). RAID 0 and RAID 1 configurations are
controlled by a dip switch accessible on the back of the unit.

When four Pro Drives (eight physical notebook 7200RPM drives) are
Striped (RAID 0) together, they can achieve more than 400MB/second of
data transfer. Or they can be used as individual volumes with RAID 1
for automatic, instant data security, according to the folks at Trans.