The Wall Street Journal is reporting that Sprint has entered into an agreement with Apple to purchase over $20 billion worth of iPhones over the next four years — that’s around 30 million iPhones. It’s said that Sprint won’t even break even on the transaction until 2014, which is surely a huge risk on Sprint’s part, but why? 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. Hit the break for more.

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.

In this scenario, the iPhone 4S Apple will introduce tomorrow will feature the following:

A low voltage Apple A5 CPU (it won’t be the same as the iPad 2 chip, clock for clock).

Updated front and back camera sensors. FaceTime HD in the front, 8-megapixel 1080p HD video recording in the back.

Multiband 3G Qualcomm chipset — North American & International GSM/UMTS/HSPA bands for AT&T and Global carriers, North American CDMA & International GSM/UMTS/HSPA bands for Verizon and Sprint.

NFC support.

Metal or “premium” plastic on the back case.

And here is what my source said about the iPhone 5 that will launch as a Sprint exclusive:

Faster CPU.

Larger 4-inch screen, similar to LG’s NOVA display but with a higher resolution.

1GB of RAM.

Slightly larger design overall, but thinner and with a larger battery.

32GB of storage.

iPhone 5 exclusive software and APIs (Assistant).

Dedicated Assistant button, possibly integrated with the new home button, “think gestures or a two-stage button like a camera shutter key).

I told my source that even if Sprint paid Apple hundreds of millions, a Sprint iPhone 5 exclusive still would never happen. $20 billion in guaranteed iPhone sales, though? We’ll see tomorrow.