Demand for the iPad continues to be high, especially for the recently introduced 3G version. In fact, the iPad 3G has sold out in 13 U.S. cities, including New York City, San Francisco, Los Angeles, Chicago, Miami, Boston, Seattle and Denver.

Demand continues to exceed supply, said Apple spokeswoman Natalie Kerris, who noted that the company is working hard to ensure that supply catches up with demand for the device that sold one million units in four weeks.

It is speculated that the iPad’s large touch screens are the reason for the short supply. The iPad is still scheduled to release in nine major territories on May 28 , including the U.K., France, Germany and Canada, and countries that include Belgium, Hong Kong, Ireland, Mexico, Netherlands, New Zealand and Singapore in July.

Source: Bloomberg