For a 6AT or 4BT setup as long as your 4BT isn't screaming out massive amounts of horsepower and torque you'll most likely be able to get away with a factory Land Cruiser split (two piece) transfer case from a '81 or later FJ40 or FJ60.  For me this is also the cheapest option as I already have the case.  To get the NV4500 to mate to the split case you'll need an adapter most likely from Advance Adapters that runs in the area of $630.

For a high torque scenario like Alan Lungi's 4BT FJ55, or a 6BT swap, the NP 205 is considered one of the strongest transfer cases out there.  It can be mated to a number of transmissions including a NP 203 tranfercase doubler.

To be honest I'm not too knowledgeable about all of the transfer case options out there other than my knowledge of Land Cruiser cases and I've recently learned the NP 205 is a pretty darn beefy t-case too.  I'm somewhat familiar with "dual transfer case" setups which can serve as various adapters for whatever t-case setup you plan on running.
 

the 

This way you can retain the factory offset axle positions and with the Advance Adapters crossmember for the NV4500 you should be able to more or less bolt it all in place other than some what minor custom work.  If you choose to replace your axles and take the Dana 60 route then your t case options are enhanced greatly because you'll have a centered rear axle and there are many more transfer cases that can run centered rear axles versus both front and rear off set axles like Land Cruisers or Land Rovers..

One thing to keep in mind is that you can always blow up a t-case.  I have a friend who's got a stock powered 2F who's blown up 4 t-cases.  So, with that in mind make sure you choose your t-case wisely.

You might also want to check out the doubler/crawlbox section too which can server as your adapter.