Ok this is my last update because the stream of information for this is rather slow. It is believed that Dragonball Kai will indeed be cropped to widescreen like the US DVD sets but it will be cropped according to the relevance of the scene, so say they have the option to crop out the bottom of Roshi's shirt or the top of his head, they'll do the shirt as opposed to the "universal cropping" of the widescreen DVDs. For now on anything you need to know about Dragonball Kai you can find here:

http://www.daizex.com/general/tidbits/kai.shtml

Oh and as a sidenote I finished DBZ a couple weeks ago and I'm cruisin through GT, if anyone wants some episodes let me know via pm.