They had a first sample on display in June http://armdevices.net/2011/06/21/freescale-i-mx6-quad-core-reference-design-at-ftf-2011/

I don’t know if there are delays or not. It seemed to work quite well with Honeycomb on this demo from October.

For example Tegra3 is maybe only being released in very limited number of devices for consumers before the end of the year, that is probably why Transformer Prime only starts selling December 19th and my guess is Transformer Prime will get out of stock pretty quickly. Mass stable availability for quad-core in consumer devices is more likely to be around second quarter 2012 something like that, also for Tegra3. I think the Freescale representative simply says he expect this to be for sure in full mass production by Christmas next year. But a processor needs to go through several steps to be with a good enough yield to be mass production, meaning shipping in millions of devices and being stable.