DaringFireball's Gruber has followed a similar argument: The iPod touch pricing, at $299, is not Apple's frame of reference for pricing a small iPad. "Don't worry about comparing the price of the new smaller iPad to the iPod Touch," he writes in a . "It's a different category. Compare it to the price of competing tablets and to the regular iPad. That's all that matters."

The key difference is between the iPod touch and the small iPad is the former is miniaturized. "It's true that smaller generally implies cheaper, but miniature carries a premium," Gruber argues. "The 13-inch MacBook Pro is smaller than the 15, and thus cheaper. ... But the iPod Touch isn't just smaller than the iPad -- it's miniature. Gadget prices tend to follow a U-shaped curve: big is expensive, small is cheap, miniature is expensive."

If you include Apple's fourth-generation iPod touch into the product matrix, you can see a clear, almost precise progression in price across the touch, iPhone, iPad and possible small iPad product lines, as in prepared by Horace Dediu, founder of Asymco. [At this writing, the was offline, and the link is to an Apple 2.0 blog post at Fortune, by Philip Elmer-DeWitt. His .] 

John Cox covers wireless networking and mobile computing for Network World. Twitter: http://twitter.com/johnwcoxnwwEmail: john_cox@nww.com

in Network World's Anti-malware section.