Well from what I'm getting on the forums, sounds like the publisher is starting, if not already taking over (like they did with the media, no more FF). If this is true then it's not up to reverie anymore, It's up to the publisher on when they want the game to be release (but there might be some negotiations between the two).
If you look at when the betas have lasted, most have lasted between a month to a month and a half. Which means the 4th beta hopefully should be starting the end of this month or the beginning of december.
"90% of what is considered "impossible" is, in fact, possible. The other 10% will become possible with the passage of time & technology." -Hideo Kojima