I ordered mine with the 6-Speed and the availability of a stick was a major reason that I choose the Nitro over some other mid-size SUV's.
I don't know the maker of the tranny but here is some info on it:
It is an "NSG 370" if that means anything to you
* Triple-cone Synchros on 1st & 2nd
* Double-cone Synchros on 3 & 4
* Single-cone Synchros on 5 & 6
* High-strength Multi-rail steel shift mech
* Hard-finished gears
* Hydraulic dual mass flywheel clutch system
* 2-pc aluminum case with integrated clutch housing
* Ratios: 4.46, 2.61, 1.72, 1.25, 1.0, 0.84 Reverse 4.06
Looks to me like you can start in 2nd with this gear and the 3.21 rear end.