As far as iPhone 6 rumors go, few are more prevalent than the ones speculating Apple (NASDAQ:AAPL) will introduce two different sized devices to market later this year.

To be sure, we're already aware Apple knows the iPhone 6 needs a bigger screen. What's more, the latest supply chain rumblings support that assertion, saying one version will feature Apple's usual 4.7-inch display, while the other iPhone 6 could incorporate a massive 5.5-inch screen and be marketed as a "Phablet" of sorts.

According to the Fool's Steve Symington in the following video, however, Apple is walking a fine line between success and frustration by narrowing the gap between its phones and smaller tablet offerings like the iPad Mini. As a result -- and though Steve notes Apple has almost certainly certainly weighed the benefits of doing so -- shareholders need to remain cognizant of the risk a larger iPhone 6 brings in potentially cannibalizing iPad Mini sales. To hear Steve's full take on what this means for investors, please watch the video.

Steve Symington owns shares of Apple. The Motley Fool recommends and owns shares of Apple. Try any of our Foolish newsletter services free for 30 days. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.