well, there's rumours that vodacom said it would be released at the end of september, but there were also rumours saying that it would be released on 22 august, so im reluctant to believe that. i doubt that vodacom would launch the iphone without having launched a marketing campaign at least 2-3 weeks before the release. i wont be surprised if they only launch the iphone only at the beginning-middle november... that way people get exposed to it and the hype is at its biggest right when its time to do christmas shopping.
also, vodacom will claim to have limited stock, i have no doubt about that. i remember reading about how orange in france said it had limited stock and would only sell a certain amount of iphones from each store, tell customers that they'll only get stock in a few days and then start selling them again the next day as if they hadnt run out of stock and then repeat the same story. clever, yes. ethical, no. reason why they did it? probably to create the impression of the iphone being very scarce and sought after, and we all know that if we cant have something then we only want it more.
as for mtn getting the iphone, maybe. but not yet. vodafone would've most likely arranged with apple for a set period of exclusivity in countries it operates from which did not already have the 2g iphone.