A Guardian online article states that the next-generation iPhone has been delivered to carriers for field-testing. Citing some sources, Charles Arthuer writes that the "boxes in which the new iPhone hardware is encased have been transported to carriers for testing. This is an important step in the release cycle for any phone."
"The next iPhones go for their testing inside locked and sealed boxes so that the carriers can carry out checks on their network compatibility in their labs. It's very high security, as you could guess; my understanding is that barely anyone inside the carriers gets to open those boxes, and even when they do the hardware is encased in a dummy body which means there's no clue to what the actual phone will do. This, by the way, is what led to "Antennagate": there simply hadn't been enough people outside Apple who had tried the iPhone 4 at length in its real form to discover the problems with its reception."
"You can bet that Apple has come up with some sneaky scheme that would instantly identify any leak of a phone photo from any of those testing labs; and you wouldn't want to be the carrier whose employee had done so. (The employee probably wouldn't stay employed very long either.)"
Either way, the new iPhones are in the system, which means they now just have to get approval - which will probably only take a few weeks at most - and can then be signed off for manufacturing.
Boy Genius report that "According to confirmed information we have received from a reliable source at Canadian carrier Telus, Apple's iPhone 5 looks to be touching down on October 1st in Canada. In the past, Apple has flip flopped between releasing its iconic smartphone in the US first and then in Canada, or launching its smartphone simultaneously in the US and Canada as it did with the iPhone 3GS."
iPhone Air mockup by Federico Ciccarese: