I ordered my 2011 X on Sept. 3rd after two weeks of delaying it (didn't have time to stop at the dealership). Seeing as I don't even have a build date (I should point out others who have ordered 2-3 months after me have build dates, and yes this pisses me off to no end) I'm looking at late February at the earliest. I would imagine 2012 models would start rolling out in October-November 2011.
The Ford rep on the facebook page, as well as factory workers at the Chicago assembly plant have both stated that since this is a brand new model/revision, they are put through extra quality checks. For example, instead of doing the full inspection on 1 out of every 50 (or whatever), they are doing it on all. They say it's more than the usual 10-point checklist (has tires? body panels not falling off? rolls without noise? doesn't explode?). This is another reason for the delays for getting them to dealer lots.
The more time any vehicle is given to mature, the better it is. I work as a software programmer, I live and die by this concept, lol. Thing is, you have to draw a line in the sand and say "ok, this is good enough" or you'll never drive anything (same concept can be applied to buying a computer, technology is always changing, if you keep waiting, you'll never buy anything).