While Amazon has yet to confirm anything about its long-rumored tablet, new details have emerged about two new versions of the Kindle e-reader that could appear in the third quarter of the year. According to The Wall Street Journal, one will have a touch screen while the other will be an “improved and cheaper” version of the current device. Both will continue to use electronic ink technology, which gives text on the Kindle the appearance of ink on paper.

The e-reader market is growing quickly, and the Kindle’s aggressive pricing has appealed to consumers. It’s not surprising that Amazon is introducing a new version. But Amazon’s entry into the full-color, backlit tablet market, which is also expected to happen before October, presents a potentially significant disruption.

As we reported on July 8, Apple’s iPad is way ahead of its competitors in the tablet space. But counting e-readers as tablets, Amazon ranks second, outpacing every full-color tablet except the iPad.

Apple and Amazon, the two companies at the top of the tablet heap, both have vast libraries of books, music, movies, and other media easily available on their devices. Amazon, as a dominant online media retailer, poses a threat to Apple’s iTunes ecosystem. A compelling full-color tablet offering Amazon’s wealth of content could certainly compete for the media appetites of tablet users.

Citing people familiar with the product, The WSJ reports that the tablet will have a “roughly nine-inch screen,” putting it in the same device category as Apple’s 9.7-inch iPad.

We reported in April on rumors that this device would be manufactured by Samsung, which fits with today’s report that Amazon is outsourcing production to an Asian manufacturer.

Other Android tablets, such as Motorola’s Xoom and Samsung’s Galaxy tab, have not sold enough units to compete with the iPad, but Amazon’s strong position as a media outlet would be a killer feature. Combined with an aggressive price, this long-rumored tablet could test Apple’s vision of what consumers want out of their touchable devices.