Last iMore heard, the iPhone 5 was still on track for an October, 2012 release, and since Apple has succeeded in getting a newer, smaller nano-SIM standard passed, Europeans carriers are now reportedly placing orders for the tiny new chips in anticipation of the launch. The Financial Times says it's because carriers don't want to get caught flat-footed again, the way they were when Apple switched to micro SIMs with the original iPad and later, the iPhone 4.
One informed person said that the major networks were keen to be ahead of demand this time, however. He added that the iPhone 5 was likely to be similar sized as the iPhone 4 although slimmer and with a fully metal body.