Re: 6-Speed Box for 2012?
If Chrysler wanted to market the 545RFE as a 6 speed they'd be doing it now.
There's a lot of speculation over future transmissions. We do know that the Mercedes-sourced W5A580 (currently mated to the Pentastar) will eventually be replaced, and right now the best info we have is that the 2013 model year will be when that happens. Other vehicles are definitely getting the new one for the 2012 MY, and the GC isn't necessarily out of the running for that, but it just isn't looking likely. Possible, but not likely.
As for the 545RFE, it will probably also get replaced, but again, not likely for the next model year. There's some other threads discussing a possible 8 speed box, but it's farther out than the 6 speed.