It's all just speculation at this time. I could name a half-dozen
DVC resorts which have been planned over the years and later cancelled. The latest was a DVC at Ft. Wilderness for which Disney actually obtained construction permits around 2010. Three years later and there has been no movement.
Disney has gone thought the design process for a DVC Polynesian a number of times over the years. This one could actually go forward...or things could be delayed another 10 years.
Physical construction normally takes about 2 years. When bulldozers start moving dirt, then we can begin speculating. This latest rumor claims construction could begin before the end of 2013. If so, rooms may begin to open in late 2015. That's as reasonable as the guesstimates can get right now.