When it comes to Apple's tablet rumor, the plot thickened today.

Just yesterday, Apple sources said there would be no Apple tablet come Sept. 9 at an event Apple is reportedly planning in San Francisco.

However today, Market researcher Richard Doherty told BusinessWeek that Apple has developed two tablet computers prototypes: a 6-inch oversized-iPod version and another with a bigger display.

According to Doherty, the 6-inch Apple tablet, which we have been hearing about for the past month, will be mainly made for watching videos, playing games, and reading e-books. The second model will have a larger screen and will be able to run all Mac applications, including audio/video editing and graphic animation, he said.

The researcher speculated that the smaller Apple tablet would cost about $679 and will probably run on an iPhone-based operating system.

However, this isn't the first time that a second Apple tablet is rumored to be in the making. Late last week, Gizmodo quoted an unnamed source also saying the Apple tablet would come in two editions; one with a webcam and one for educational use. Gizmodo's source tablet also went for around $700.

Till this point, Apple has remained mum any of its plans for the Sept. 9 event, which will likely mark Apple's final product launch of 2009.