While it’s widely known that Apple makes most of its money from hardware, one analyst predicts that the various content sold on the forthcoming iPad will equal nearly 30 percent of what Cupertino makes on the device by 2011.

It’s anyone’s guess what will happen with the iPad when it starts shipping on April 3rd, but analyst Brian Marshall with Broadpoint.AmTech has some educated guesses, according to AppleInsider. Marshall issued a note on Tuesday morning predicting that the content revenue alone will top 10 percent of total iPad cash by December, 2010 -- and that number will triple by the end of 2011.

“We believe the iPad offers a rich media experience that will translate into a content-based recurring revenue stream over time,” Marshall writes.

Should Marshall’s prediction pan out, it would be a flip-flop for Apple, who has historically claimed that the App Store and iTunes in general do not create significant revenue for the company. In fact, in January of this year, chief financial officer Peter Oppenheimer noted that Apple runs “a bit over break even” for both storefronts. The official company line is that the two stores are not intended to be big profit machines, but instead a “loss leader” to attract customers to their hardware.

Analyst Marshall had previously forecast that Apple would ship 2.2 million iPads in the 2010 calendar year, but has raised his estimates to 4 million units. However, “if the device lives up to its potential,” the analyst can see Apple shipping more than 7 million units this year -- a figure that’s much higher than current Wall Street estimates.

And what about the media’s often pessimistic view of the device itself?

“We note the vast majority of the naysayers have not yet had the opportunity to use the iPad on a firsthand basis,” Marshall writes. “As we stated in the past, we were hooked after the first 15 minutes of use. In our view, the true genius of the device is its media/content specs (e.g. e-books, newspapers/magazines, apps/games, movies/TV episodes, etc.), which we believe will be recurring in nature.”

You can take the plunge for yourself when the iPad goes on preorder at Apple’s website this Friday, with the Wi-Fi model available on April 3.