It to fully stock its stores with the iPhone 3G in 2008. The company had similar problems for the iPhone 3GS a year later.

Once the initial rush is over -- which will likely continue through the launch of the 3G-equipped iPad a month or so after the WiFi-only model on April 3 -- sales will drop off until the back-to-school run in mid-to-late summer, said Gottheil. "I see a lot of upside for the iPad during the year, with strong sales in the back-to-school quarter. And it will be a very attractive holiday product."

Survey data seems to back up Gottheil's sales projection. According to ChangeWave Research, which in the first half of February -- days after Apple CEO Steve Jobs unveiled the iPad -- sales of the iPad will gain momentum for at least six months after launch.

Of the people polled who said that they are likely to buy an iPad, only 6% said they would put down their money in the first week after its release. That number climbed to 20% for two to three months after launch, and 23% for the four-to-six month period.

Paul Carton, ChangeWave's research director, cited the low number who said they would immediately buy an iPad to challenge the thinking of analysts like Gottheil and Marshall. "I don't think you'll see in the first weeks people pounding down the doors," he said. "It will take off slower, and build."