Disclaimer: None of this has been officially announced or confirmed by Bethesda to my knowledge. Im not sure about the source whatsoever so everything you see, I would take with a grain of salt. None the less I thought it was interesting and it given me new hope either way.

http://www.bubblews.com/news/660463-fallout-4-announcement

As you said, this isn't confirmend by Bethesda, but their's always PAX east, and you usually find Bethesda there. I think it's in Boston this year too, that'll be interesting

We already are talking about this http://www.gamesas.com/topic/1463405-fallout-4-speculation-suggestions-and-ideas-132/?p=22767622, which is where this was first posted