Apple has begun production on an incremental upgrade for the iPad 2, presenting the possibility of the first instance of mainstream and high-end iPad models, according to an analyst.

"Apple is...expected to roll out a premium version of iPad 2--a higher resolution screen, front-/rear- facing HD cameras--in the current quarter," Ashok Kumar, an analyst at Rodman & Renshaw, wrote in a research note today. This follows similar reports about a high-end iPad in the works.

"It looks like Hon Hai is going into production with this new SKU," he said in a phone interview, citing supply chain sources.

Because Apple won't "sunset" the current iPad 2, just announced in March, it will be a model that "probably appeals to the publishing vertical and some other select segments," he said.

Wayne Lam, an analyst at IHS-iSuppli, said in an interview today it's "definitely within the realm of possibility. The true third-generation iPad would be on a yearly [timetable]. That said, I wouldn't preclude anything they could do incrementally."

Lam continued. "Anything modular that's in the device can be easily upgradeable. For example, the 3G module. Potentially they can upgrade to a 4G module. And the display. If it contains the same footprint, size, power requirements and if the OS supports higher resolution, [it's possible]," he said. iOS 5, due this fall, would need to support the upgrades, he said.