After four years of waiting, it appears that Sprint will finally get the chance to carry Apple’s smartphone on its network. Among other things, Apple is expected to announce a new partnership with the carrier at tomorrow’s iPhone event.

A few moments ago, The Wall Street Journal (who confirmed the Sprint-bound iPhone back in August) posted an interesting article regarding the new partnership between Apple and the third largest US operator.

The deal reportedly requires Sprint to purchase 30.5 million iPhones over the next 4 years, costing the company nearly $20 billion. But why in the world would Sprint make such a staggering commitment? BGR believes it’s for iPhone 5 exclusivity…

Sprint has essentially ‘bet the company’ on the iPhone, as the carrier will reportedly lose money on the smartphone deal until 2014. The wager could pay off big time though, as the operator is now rumored to get iPhone 5 exclusivity this Fall:

BGR’s Jonathan Geller:

“I have been going back and forth for weeks with one of my incredibly solid industry contacts on a piece of information that I couldn’t really process at first — information that is so unbelievable, even from a source this solid, that I couldn’t report it. With this new WSJ report on an Apple/Sprint deal, however, it doesn’t look so crazy.

I have been told that Sprint will be getting the iPhone 5 — yes the real iPhone 5, not the iPhone 4S — as an exclusive. And it will be a 4G WiMAX device. AT&T and Verizon would launch the iPhone 4S and get the iPhone 5 some time in the first quarter of next year as an LTE device. Globally, the iPhone 5 might be available as a 4G HSPA+ device.”

Geller goes on to say that his source confirmed iPhone 5 specs, including a larger 4-inch screen and a gesture-based home button. He also mentions that the handset would be slightly larger than other models, but would be much thinner.

While the news is definitely entertaining, it seems pretty unlikely. Word on the street is that Sprint was planning on dumping its WiMAX 4G technology in favor of the more popular LTE platform. WiMAX isn’t used by any other major carrier.

On the other hand, as Geller speculates, $20 billion in guaranteed iPhone sales could be enough to sway Apple to do something crazy. Like giving the third largest carrier in the US exclusive access to its flagship 4G smartphone.

On top of its Apple partnership, Jeff pointed out to me that Sprint’s WiMAX network has been around a lot longer than the other 4G infrastructures, so it’s by far the most tested. The carrier started rolling out WiMAX back in 2008.

Even with reasoning, the entire theory sounds pretty sketchy. We still haven’t seen any leaked iPhone 5 parts, or any other evidence of the device for that matter (other than cases). Regardless, tomorrow’s iPhone event just got a little more interesting.