"Approximately one out of every ten iPhone 3G buyers are likely to be international pre-paid subscribers who'll find themselves paying in excess of $600 for the touch screen handset, according to a new report."Although VFNZ looks to be not offering pre-paid.. it might give an indication to handset pricing.
With Vodafone italy selling the phone unsubsidised for 499 euros and reports that AT&T are subsidising the cost of the phone by US$235 then ~US$600 for the cost of the 8GB model isn't unrealistic.
There are some reports that the 3G model is costing Apple as little as US$100 to produce. That's a fantastic profit margin!