(Updated with other slippages)
Supplies of the iPhone 5c -- which just went on sale this morning
-- are mostly stable, checks show. While shipping times have grown to 1-2 weeks in Hong Kong, deliveries are still set for September 20th in all other launch regions. The closest exception to this is at Sprint in the US, which says that "some phones" will ship in up to 2 weeks, and that the yellow 32GB model is due in 3.
Demand for the 5c so far appears less intense than for past new iPhones. The device is essentially an iPhone 5 with a plastic back, however, and not radically cheaper than the 5s. A 16GB 5c is $549 unlocked, versus $649 for an equivalent 5s. Even on a two-year contract, the 5c is $99 versus the 5s' $199.
5c shipping dates have slipped as well. An unlocked, 16GB yellow 5c is now only shipping by the 25th from Apple's online store. In Canada, some models may only arrive as late as the 24th.