WHAT? That's insane. As it is, a lot of their customers are Android, or don't have smartphones. They also have an even bigger legacy of Android, since they didn't have the iPhone for such a long time. I'm trying to figure out the math on Virgin and Boost customers getting iPhones, but I can't make it work out unless Apple agreed to sell the iPhone at a significantly lower price to Sprint in exchange for the volume of units. The only thing I can think of is Apple is selling Sprint the iPhone 4 CDMA for around $300, and they will sell it on Boost and Virgin for $299. That could sell like hotcakes, if Sprint has the exclusive on a pre-paid iPhone with $35 unlimited data/text or $50 unlimited everything. That would, however, explain the 2.5GB soft cap and $10 increases in plans on VM in preparation for this.
Admittedly, if the contract with Apple goes for 3 years or more, they could have some re-sales on new iPhones, but even that would need 15-20 million iPhone customers. Does AT&T even have that many? Something is not right with the rumors that we're seeing.
Oh, and what would 30 million iPhones do to Sprint's EVDO network? Granted, most of the Android people are on WiMAX, but still, that's a lot of data traffic coming in.
You do know that Boost and Virgin both sell Android phones, right? The various rebranded variants of the LG Optimus One has been one of the biggest hits in the prepaid world due to its budget-friendly low-end specs.
Even if Sprint does decide to offer the iPhone through Boost or Virgin, it's not going to be cheap; you'd probably be looking at $399 and upwards. Apple sells their phones to the carriers for the same price as we would have to pay for an unlocked model ($549 and up); there's only so much of a subsidy Sprint can give prepaid customers before it completely kills their bottom line since, among things, they are a flight risk (in the sense that there is no contract binding them to paying back whatever subsidy may or may not exist) and Sprint's finances aren't exactly solid.