What we don't know is how many Surface RT units Microsoft has manufactured for this initial run. The $599 and $699 models, both of which include the much-ballyhooed keyboard covers, continue to be available for delivery by October 26, which either suggests that interest isn't so high that people are clamoring for any Surface model they can get, or that Microsoft's margins on the upper-end models are higher, and that they've simply chosen to allocate more of them for shipment.
At the very least, this early sellout is a sign that at least a few people are eager to get Microsoft's first serious attempt at building PC hardware into their hands. Early Android tablets were hampered by the fact that they cost the same amount as the much higher-profile iPad, and have only found serious mainstream success after models like the Kindle Fire and Nexus 7 brought tablet prices down. With the amount of money and time that Microsoft has been spending on advertising and PR for Windows 8 and the Surface, it's probably hoping to avoid a similar fate.
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