WD's Raptor Still Stands Alone
A final reason why we have yet to see other 10K SATA drives on the market is that a faster rotational speed is not the only way to increase the performance of a hard drive. While a higher RPM level certainly is the obvious way to increase a drive's performance, the logistics of moving past 7200 RPM lead to increasing costs, more expensive parts, and possibly a higher failure rate. Faster rotational speed also leads to increased noise and heat production.
Other methods can be employed to increase disk performance without the need for a higher rotational speed. Perpendicular recording is one such measure. Though this technology mainly increases the capacity (gigabytes per square inch) of hard drive platters its implications for increased efficiency, as well as reliability, are worth noting. Increasing the GB/si measurement of a platter means smaller drives can be used and rotational speed is not as important a factor. Other advances, for example native command queuing (which is found on Western Digital's 150GB Raptor), have started to become popular and have a positivel effect on performance.
In summation, the lack of other 10K RPM SATA 3.5" drives may seem like a disappointment to the performance enthusiast, but there are sufficient reason to understand why this is. The lack of audience, increased cost, increased risk to the manufacturer, and investment in SCSI means that Western Digital will probably be the only company producing 10,000 RPM SATA drives for awhile. Consumers have little reason to be disheartened about this, WD's Raptor series has, overall, proven to be reliable and their performance is top-notch.