I think it's safe to say that Cars Land at WDW is now dead.
That rumor got started in the Fall of 2012 when Al Lutz on Miceage reported that after the wild success of Cars Land's opening summer several other Disney properties were after it; specifically Tokyo Disneyland and Disney's Hollywood Studios.
The Tokyo rumor continues to bubble along, but it was reported by Miceage in 2013 that the initial plans for a cloned Cars Land for DHS were shelved after soil tests proved it would be near impossible to build the towering and massive Cadillac Range and Ornament Valley rock formations in the soft Orlando swamps.
I think there's something to that. I'd hate to be the soil engineer who has to try and keep 12 acres of 125 foot tall steel-framed rockwork upright and stable in the Orlando soil environment.