I was wondering because the more I think of it, is there a lot of time to actually set-up all the sets and props, ect.. for VII? Or maybe I'm just imaging things since I'm half asleep...
Filming began in June 1997 and ended in September 1997, so all sets and props for TPM were completed during that time frame. Filming for Episode 7 will probably be from late-spring 2013 to early fall 2013.
Going from The Beginning documentary, which is part of The Phantom Menace DVD extras, George Lucas started writing Episode I on November 1st 1994. Pre production began at some point in 1995 (concept art, location scouting etc...) Sets and props began being built late 1996/early 1997 and cameras rolled at Shepperton Studios in June 1997. So it was about two and half years from Lucas beginning writing the script to anything actually being put on celluloid. And a further two years from the start of filming to the film being released in cinemas.
_ _ _ _ This tends to suggest, as others have speculated elsewhere, that Episode VII has been in the works for quite a while already.
Or else, look at the time frame for ROTS, with technology as it is, extensive sets are no longer needed, and films can be spun out in much shorter time frames.
Except that ROTS had more sets and practical models and effects than any other Star Wars movie. And it took three years, as long as most of the Saga.
I am still a little bit surprised by the timing of the first film. 2016 seemed more doable to me initially, but I guess it is possible. I hope it's not rushed at the expense of quality.
Let's not forget that GL probably has had the art department working feverishly since he started writing the treatments for the ST. That would mean a whole lot of production concepts already in the pipeline that KK and the director can choose to use or not use. Also, GL made the PT by himself essentially -- most expensive indy films ever! Disney has the resources to cover all bases in getting Episode 7 produced on time for 2015, albeit maybe later than a May release. I don't think they would have made such a definitive announcement otherwise.