Here is an article on Yahoo that explains most of the details behind these new vehicles. They are looking to make these new models different in an interesting way.
The Chevy Tahoe used to be available in a shorter version of a Suburban in the 1990s, and some of them had third seats in them; but slim to no trunk space would be available. This Tahoe and the Suburban always had similar features, whether it would be the two doors in the rear or the option to only open the rear window to reach inside and remove cargo. The older Suburbans in the 1980s had the tailgate option after the window rolls down.
In addition, choices were either automatic or manual hubs for if you had four wheel drive.
Feel free to read the Yahoo article at your leisure, I am certain that very soon articles about these new SUVs will hit the newsstands and you will able to read them in print at a Barnes and Noble or a local public or college/university library.
Technology never seems to stop advancing.