Apple's (AAPL -1.17%) iPhone 6 may still be months out, but that hasn't stopped the rumor mill from attempting to foresee what Apple has planned for its next smartphone launch. While many details about its next iPhone lineup remain a mystery, there's one commonality among most speculation: Apple's newest smartphones will likely have larger displays.

Taking speculation one step further, MacRumors has even commissioned renderings of alleged iPhone 6 design drawings of 4.7-inch and 5.7-inch models (both larger than Apple's current iPhone 5s display of 4 inches). Could this be what the iPhone 6 looks like?

MacRumors renderings, by Ferry Passchier, of the alleged 4.7-inch and 5.7-inch sixth generation iPhone lineup. Photo used with permission.

The photos above were based on the alleged iPhone 6 design drawings below. The drawings were first published by Japanese magazine MacFan.

Alleged iPhone 6 design drawings published by MacFan

MacRumors' Arnold Kim notes that design leaks like these are not uncommon leading up to a new iPhone launch. However, they are not always accurate, Kim says. "In some cases, as with the iPhone 5C, early design leaks turn out to be quite close to the final product, though in other instances [like the iPhone 5] they turn out to be inaccurate."

What might the new lineup look like next to the iPhone 5s and the iPad Mini?

MacRumors renderings, by Ferry Passchier, of alleged 4.7-inch and 5.7-inch sixth generation iPhone lineup (middle) next to iPhone 5s (left) and iPad Mini (right). Photo used with permission.

Why Apple needs a larger iPhone
Apple seems to be embracing the idea that a larger iPhone is necessary, making the likelihood investors will see these alleged models greater. Recent internal Apple documents that surfaced in court in an Apple-Samsung trial suggest the company is well aware of the growing demand for smartphones with larger displays. In a 2013 slide deck, one slide titled "Consumers want what we don't have" showed that a big chunk of smartphone shipment growth in calendar 2013 came from smartphones with displays larger than four inches -- 91 million units of the year's 228 million unit incremental growth.

A number of Apple analysts have begun to make attempts at estimating the impact of a larger iPhone on Apple's financials. Longtime Apple analyst Brian White of Cantor Fitzgerald is one of them. After his "tech tour" in China recently he shared the following in a note to investors:

In our view, the iPhone 6 with a larger screen (e.g., 4.7-inch, 5.5-inch) has the potential to meaningfully accelerate Apple's growth trajectory in China during (the second half of 2014). We have not heard this type of excitement in China around the iPhone in at least two years and thus believe this could be a very special iPhone launch for Apple.

If Apple is planning to launch an iPhone with a larger display, the move could serve as an excellent catalyst for the stock. Revamping its iPhone lineup with a new form-factor meant to cater to a proven market may help Apple accelerate the year-over-year growth rate of its iPhone business. In Apple's first fiscal quarter, the unexpectedly low growth rate of 7%for the business surprised investors.