If you have a fancy enough plan and seniority with the carrier, you will probably be able to get a shiny new iPhone every year if you ask. I've seen it done before, as annoying as that is.
Most prepaid/"no free phone" plans are a ripoff anyway - because there are tons of people willing to pay for them. That is - people that do not wish to sign a contract, those that have really really bad credit, those that haven't paid their last carrier's phone bill for some reason, and anonymous people that pay cash and don't want a paper trail for some reason or another.
With the iPhone, it almost always costs more to go prepaid/contractless. $649 for an iPhone.... with tax in California that damn thing would cost at least $700. Even if you go with Virgin Mobile ($35 a month, NOT EVEN POSSIBLE) you'd be paying ~$64 a month over the course of 2 years.
In reality, I think the bare minimum you can run an iPhone for is $40/month, so you're right back at the contracted price anyway.