Microsoft has exhausted its initial supply of the lowest-priced Surface RT tablet, which now is backordered by three weeks.

On Wednesday, the company's pre-order website noted, "Order now for shipment within 3 weeks" for the $499 32GB tablet.

That model lacks a cover-cum-keyboard.

Microsoft yesterday kicked off pre-orders for the Surface RT, its first entry into tablet design and manufacturing. The Surface RT comes in three configurations: a 32GB model at $499, a 32GB device with a Touch Cover for $599, and a 64GB model with that same cover at $699. Touch Covers are also available separately for $119.99, and the Type Cover, a slightly thicker keyboard with key travel more like that of a lightweight notebook, costs $129.99.

The two higher-priced SKUs, or stock-keeping units, remain available for delivery by Oct. 26, the official launch date for Windows 8, its spinoff Windows RT, and hardware powered by both new operating systems.

Although the entry-level Surface RT was out of stock Wednesday, the Type Cover -- which one might expect would be ordered alongside the keyboard-less tablet -- was not. Orders for the Type Cover will be fulfilled by Oct. 26, Microsoft said.

Customers may be opting for the lowest-priced model -- and passing on a keyboard -- simply to save dollars.

"The entry-level product includes no typing solution and is pretty transparently an opening price point gambit," said Stephen Baker, an analyst with the NPD Group. "But there's no way to know how many people bought, or didn't buy, one of the covers."

In other words, Baker continued, don't read too much into either the backorder or the fact that the two covers are still available.

Even so, he was surprised that Microsoft offered a cover-less Surface RT. "To some extent, without a [Touch or Type] Cover, then the Surface is just another tablet," Baker said. "With a cover, it's both a consumption and creation device."

Ever since June, when Microsoft unveiled its Surface project -- which also includes a Windows 8 Pro-powered tablet set to ship in late January 2013 -- the company has aggressively promoted the cover-slash-keyboard. In its opening television advertisement for the Surface, which ran Monday night in the U.S., Microsoft almost exclusively focused on the cover.

"Given the focus of the product, Microsoft's concept was, 'This is a new kind of tablet, a new kind of notebook. It's either one and both at the same time,'" said Baker. By offering a Surface RT minus a cover, Baker argued, Microsoft was muddying that message.

The lowest-priced Surface RT is now backordered, and won't ship for as long as three weeks.

"They could have set $599 as the opening price," Baker said, referring to the 32GB Surface RT that does include a Touch Cover.

He was also dismissive of any interpretation of the quick sell-out of the $499 model. "[Sell-outs] don't ever really mean anything," he said. "They could have made just 10 of them, then said, 'We're out!'"

Nonetheless, out-of-stock reports are not uncommon, especially for new devices. Availability of Apple's products, particularly the iPhone and iPad, sometimes even its Mac notebooks, are regularly tracked by the technology media and bloggers as one of the few available clues to sales.

Microsoft may mention the Surface RT, and perhaps hint at early sales, during its upcoming quarterly earnings call with Wall Street analysts. The conference call, which will cover the quarter that ended Sept. 30, is slated to start Thursday at 5:30 p.m. ET.

Microsoft's pricing of its Surface RT tablet was called 'aggressive' by some analysts, 'mystifying' by others, even as they remained skeptical that it's low enough to make inroads on the dominant player, Apple's iPad. What do you think -- is Microsoft's Surface tablet pricing competitive with the iPad?

<a href="http://polldaddy.com/poll/6616445/">Is Microsoft's Surface tablet pricing competitive with the iPad?</a>

Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer, on Google+ or subscribe to Gregg's RSS feed . His email address is gkeizer@computerworld.com.

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