If you had any doubts about Apple (NASDAQ:AAPL) launching iPhones with larger screens this year, the recent ramp in iPhone 6 related rumors should temper your concerns: Apple looks dead set on jumping in on the fast growing 4-inch plus smartphone market.

4.7-inch and 5.5-inch iPhone 6 mockups pictured with the 4-inch iPhone 5s. Image source: 9to5Mac, used with permission.

If you're not familiar with the rumors, Apple is supposedly prepping another bifurcated lineup -- this time with two phones with different display sizes. The smaller of the two will allegedly measure 4.7-inches, beating out the iPhone 5s' 4-inch display. The larger phone will come with a phablet-like 5.5-inch screen size.

Could this be the rear shell of the iPhone 6?
The most recent part leak comes from Japanese blog Mac Otakara. The site released a video on Thursday that showed what it asserts is the rear shell of a 4.7-inch iPhone 6.

Screenshot from Mac Otakara's video of alleged 4.7-inch rear casing. The alleged casing is in the middle. On the left is a mockup of the 5.5-inch iPhone 6. On the right is a mockup of the 4.7-inch iPhone 6.

As AppleInsider explains, it's worth noting that Mac Otakara doesn't mention the origin of the new part. With that said, there's certainly a chance that the final rear casing may end up differing from what was shown off in the video.

AppleInsider only calls the part a possible "engineering sample."

Piecing together other recent rumors
The most intriguing of the recent rumors are ones that are related to the 5.5-inch version of the iPhone 6. With the size so dramatically different from what iPhone users are used to, it's this phablet-sized iPhone that has faced the most skepticism -- especially considering (until recently) leaks related to the larger iPhone 6 were lacking.

It wasn't until last weekend that the first alleged display part for the larger phone was leaked. The leak came in the form of a pair of photos of an LCD display component for the next-generation phablet-sized iPhone shared by Sonny Dickson to 9to5Mac.

Alleged LCD display component for the 5.5-inch iPhone 6. Image source: 9to5Mac. Photo used with permission.

A few other rumors during the week are also beginning to suggest exactly how Apple will be differentiating the phablet-sized iPhone 6 from the 4.7-inch version.

One prediction comes from the reliable KGI Securities analyst Ming-Chi Kuo, who says that the larger version of the iPhone 6 will offer optical image stabilization, and the 4.7-inch version will not. Kuo cites both supply constraints and efforts by Apple to differentiate the 5.5-inch version from the 4.7-inch version as reasons for the move.

Another way the Apple will allegedly differentiate the larger iPhone 6, reports Chinese site Wei Feng (via MacRumors), is by offering a 128 GB storage capacity option -- something currently only offered for the iPad line. Apple will also step up its entry-level offering, starting the 4.7-inch iPhone 6 at 32 GB instead of 16 GB for the iPhone 5s, Wei Feng says.

In general, broader predictions about the phone remain unchanged. Both versions of the iPhone 6 are rumored to have a slimmer thickness than the iPhone 5s and a significantly faster and more efficient A8 processor. While the smaller phone was initially thought to launch a few months ahead of the larger version, Bloomberg reported last week that both phones are now likely to launch simultaneously this fall.

MacRumors renderings, by Ferry Passchier, of the alleged 4.7-inch and 5.5-inch sixth generation iPhone lineup. Photo used with permission.

Reading rumors
While Apple rumors, in isolation, are mostly useless for the long-term investor, when the sentiment and direction on product related rumors are viewed in aggregate, investors may get a glimpse of the broad plans Apple has for its upcoming products.

At this point, we can be fairly certain that Apple is readying a pair of larger iPhones. This will likely pan out well for the company since the market for smartphones with screens larger than 4 inches is growing rapidly, and Apple currently has no product offering in the space. Two larger iPhone 6 models will help Apple take its spot at the high-end of the important space.