The rumor mill surrounding Apple's iPad 3 is starting to reach fever pitch, with most commentators settling on a March release date.

But on Monday some analysts were predicting a later worldwide launch date around April, adding that an on-going trademark lawsuit in China may delay the tablet's release there for the foreseeable future.

It also emerged the next iPad may be far less of a technological quantum leap than most Apple watchers want, and more of an upgrade in the style of the iPhone 4s.

Addressing concerns about the tablet's rumored Retina display capability, Japan-based tech analyst Charles Annis said he believed Apple may opt for Sharp's IGZO flat panel.

Speaking to Cnet, Annis said: There's not a single commercial IGZO FPD [flat-panel display] available right now.

And if Apple does start accepting them for the iPad 3 and starts selling then in April, that would be a world's first and we do think that's likely to happen.

Contradicting rumours of a March release date for the iPad3, he added, Our thinking [for the release date of the iPad 3] is probably around April.

Aside from display rumors, other analysts were pouring cold water on hopes the iPad 3 would represent a significant technological leap on previous efforts.

Kyle Wiens of iFixit, a reliable bellwether when it comes to Apple predictions, said he expects the iPad 3 to be more of an upgrade on the existing iPad 2 rather than an entirely new product.

Speaking to PC World, he said: My guess is that improvements will be incremental, not insane--unless Apple decides to go to a quad-core.

I wouldn't be surprised if Apple calls it the iPad 2 HD, instead of the iPad 3. This means maintaining the $500 price point.

Wiens added he expects the iPad 3 to have, basically the same form factor but with double the screen resolution, as the current model, with a display resolution close to the Retina display found on the iPhone 4.

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