Very interesting -I stumbled across this forum while searching particularly about info on the 4wd system on the 2008 Nitro (a contender for my next company car). Oddly, it appears that Part-Time 4wd transfer case IS available in Canada, at least it shows up on the spec sheet (see page 3). Although I cannot tell if this includes Low Range or not, albeit that is not important to me.
I am apparently not allowed to post a web page link on my first visit, so go to dodge.ca and after you find the nitro page, there is a link to a specifications PDF on the right.
I am driving a Jeep Liberty at the moment and specifically ordered Selec-Trac (part-time/full time 4x4) over Command-Trac (full-time 4wd) particularly for driving on snowy/slushy/slippery roads. And frankly it has been fantastic in that regard.
I hope for you folks in the US that the full time system does reappear on the options list.