South Korean media is reporting that Apple’s sixth iPhone will include a 4.6-inch Retina display. As such, the Cupertino, California-based company is rumored to have already started placing orders to its suppliers for those screens, according to Reuters.

First launched by Apple in 2007, the iPhone has always included a 3.5-inch screen, even as competitors expanded the screen sizes of their smartphones. For example, Samsung’s flagship Galaxy S II comes with a 4.6-inch OLED display.

This isn’t the first time we’ve heard Apple was preparing an iPhone with a larger screen. In fact, that phone was supposed to arrive last year as the iPhone 5. In October, for instance, we reported that the company was prepping such an iDevice as late as February 2011, with plans to release the handset at WWDC in June of last year. Those plans changed because Siri, the voice recognition software, wasn’t ready and neither was iOS 5. Plus, the late Steve Jobs is said to have been unhappy with the 2011 design because it “fragmented” the iPhone.

Instead of releasing an iPhone 5 with a larger screen, Apple unveiled the 3.5-inch iPhone 4S, which looks just like the iPhone 4.

This time around, however, rumors of a larger screened iPhone may be genuine.

For one, the delay almost certainly helped Apple’s suppliers, LG Display and Samsung, improve upon the 4.6-inch display. In addition, Foxconn, the company responsible for putting the iPhone together, is probably also ready for the redesign. Finally, the time has come for Apple to unveil a radically different iPhone, after the company’s last two models looked the same.

Apple’s next big announcement could come as early as June or as late as October. We’ll keep you updated.

Updated: John Gruber has chimed in and doesn’t think Apple will increase the iPhone’s size to 4.6-inches, stating:

Lots of attention on this rumor, but no one seems to be pointing out that if it’s true, this new iPhone would need way more pixels than the current 960 × 640 iPhone display. That means every app in the App Store would need to be redesigned/resized. For this reason and others, I say it’s bullshit.

While I personally understand where Gruber is at, I disagree with the overall premise of a larger iPhone display somehow being out of bounds. We’ve gone five years with the iPhone screen remaining at 3.5-inches. This comes at a time when the rest of the industry is making larger screen (and thinner) smartphones. Because of this, I’d be surprised if Apple didn’t a least increase the iPhone’s screen somewhat; perhaps not to 4.6-inches, but something closer to 4-inches would be well justified.

Do you expect Apple to supersize the company’s most popular product?

[iPhone 5 concept: Stuff.tv]