Why Apple could sell more than 50 million iPhones this holiday season

In a research note today, Canaccord Genuity analyst Mike Walkley told investors that if rumors of a sixth-generation iPhone redesign materialize, Apple could sell more than 50 million handsets this holiday season.

The number itself isn’t overly significant — Apple sold 37 million iPhones last holiday quarter, more than double the 16 million it did the previous year — but the factors that could make it possible are…

This year’s iPhone is expected to finally include a larger 4-inch display and LTE compatibility — features that were once restricted to the Android platform. Not only will this fuel interest from non-Apple users, but it will also push current iPhone owners to upgrade. Think about it, if Apple can sell 37 million handsets on the back of a “disappointing” device, imagine what it could do with this.

But Apple’s upcoming handset has more than just a [rumored] hardware redesign going for it, there’s also increased availability. Up until the last 6 months, the iPhone has only been available on a handful of carriers in the U.S. And you couldn’t find one in mainland China. Now the smartphone is being offered by more than 10 U.S. operators — including prepaid, and multiple Chinese carriers. Not to mention ongoing rumors of a China Mobile deal.

Finally, there’s the multi-choice aspect. While the iPhone may not come in nearly as many sizes and form-factors as Android devices, the options are growing. Potential customers can currently pick from a curved-backed 3GS, a $99 iPhone 4, or the Siri-laden 4S. And pretty soon, we’re assuming, they’ll have a 4-inch display option to choose from as well.

All of these things boil down to this: Apple will be wielding its broadest and strongest smartphone portfolio ever this holiday season. And not only will the company have a shiny new handset to show off, but chances are that it will also announce new carrier availability and price drops for previous models. Mix all of these factors together, and 50 million doesn’t seem nearly enough.