With the design of the NP T-case the only thing that you are going to gain is the ability to run rear wheel drive low range. You can do that with a single lever too.
The Curries did an air shift NP a year or two ago. The front axle engaged and disengaged with a switch.
What would be REALLY handy is if someone came up with a rear driveline disconnect system that would fit under the TJ. That way you could to front and rear wheel drive like an ATLAS. I have found a lot of times when having just the front pulling is REALLY handy. I just wish that there was an wasy way to do this on the factory rubi t-case.
There is a driveline disconnect that you MAY be able to get, but I haven't been able to find out for sure.
The only problem would be getting the thing torn up on the rocks....