Do new AAA titles ever get announced during the September through December months? I thought this time of the year was always devoted to what's coming out now (huge AAA titles, new consoles, new console accessories) rather than what will be coming out in a year.... Seems to me the entire calendar year builds to the climix that is the holiday shopping season. Every console has some hit exclusive coming out to out-do their competitors and we see a hugely disportionate number of multi-platform AAA releases during quarter 4.
I just don't think the thick of the holiday shopping season is a legitimate expectation. Bethesda knows the gaming public's attention will be focused on what's about to come out, what came out last week, and what will be released in two weeks. To say nothing of the gluttony of newly-released theater films, dvds, books, music, etc.
We won't hear news about Bethesda's new game until early 2011. I say the announcement comes in February with a tentative release date of "Fall 2011" that narrows down to an exact date at E3 2011, just in time to rev up pre-order sales and announce collector's edition pack-ins.
Sure they get announced during the fall. For example, every year at the VGAs (Spike TV's Video Game Awards) they announce a handful of games. Arkham Asylum 2 (forgot the current name) was announced there. So were a few other AAA titles if I recall correctly. And my memory isn't good enough to remember any other announcements in the last few Fall seasons, but developers don't just stop announcing games during that time.
But even assuming they actually are planning on waiting until the beginning of 2011, you have to remember that January-April is still a busy time of the year for video game releases. Those are the dates during which the previous year's titles that couldn't go gold in time for the holiday season are released, and while the beginning of 2011 is already starting to fill up (Portal 2, Gears of War 3, Dragon Age 2, Bulletstorm, etc all coming out before the end of April), if the beginning of 2010 is anything to go by, it will just get even more crowded.
The point I'm trying to make is that there is no "not busy" time at the beginning of 2011 for them to announce it. September-December will be really full of new releases, but January-April will still see the the release of a lot of AAA titles too. Bethesda isn't going to wait for all these popular titles to come out just to announce it. They'll announce it when they're ready to announce it.
That said, I personally expect them to announce it close to the end of the year. Todd's comments indicated that they're ready to show it off if they have to, and they have a lot to show, but they've just decided to wait for now. September or October seems too close, and January or February seems too far away. November or December, 3 or 4 months after Todd's comments, seems just right to me. 5-6 month afterwards would make it seem as if they ran into a snag that didn't allow them to announce it earlier, imo.