Fallout 4 has been confirmed thanks to the launch of the official website a little ahead of the Officially Official Super Official Big Fallout Announcement time Bethesda mentioned previously.
The site appears to have vanished again (or has fallen over under the weight of Pip-Boy enthusiasts) but there was a video included. It's currently set to private but I've popped it here for when it does go live:
There's also this piece of game art (which you can click for a larger version) in case you fancied peeking at some of the detail in the meantime.
There's a lovely doggy.