Can one purchase a Cessna 182JT-A although it has not yet been certified?
They did have an engine out failure about a year ago which set everything back a bit.  They've had it at Osh a couple of years now.  Two years ago they were saying around the end of '14 beginning of '15.  Last summer, they were saying months.  If you're really curious, I would talk to the manufacturer in Kansas.  Dealers really aren't part of the FAA approval process...

I wouldn't read too much into the range calculator.  I would imagine that they would be adjusting numbers numerous times before release as they get more data.