Several industry sources have said that Western Digital is working on a 20,000 RPM Raptor hard drive.
According to several sources close to the hard drive industry, Western Digital is working on a 20,000 RPM Raptor hard drive to combat the increasing pressure from SSD manufacturers.
I bet that it won't really be that much faster than anything else out there.

SOURCE: http://www.bit-tech.net/news/2008/06...0-rpm-raptor/1