Apple may be not only working on a 10-inch tablet, but also in 13 and 15 models, one running Mac OS X, Gizmo said on Friday citing a source that has always been 100% reliable.

This source claims that the two touchscreen prototypes-made of aluminum, but on the shape of big iPhones-were in a factory in Shenzuen, China. The company has a tight relation with Apple but it's not FoxConn, a well-known manufacturer of products from Apple and other major brands.

One of them was running Mac OS X 10.5.,  going against rumors that Apple's tablet will function more like a giant iPhone.

But the source didn't know if these were built for demonstration purposes, or if they were preproduction units.