No such animal in the USA.
So, you can:
1. Buy a used truck with an engine and manual transmission and figure out how to adapt your choice of t-case. Isuzu's did not come with 4WD in the US, so there will be no transfer case with the manual trans, unless you get it from Oz.
2. There are companies that make adapters for the auto trans, not sure about the manual. Any competent 4WD shop or fab shop should be able to make an adapter for you custom, but it will take some engineering to ensure proper fit and operation. Because that transmission did not come in 4WD in the NPR, there is not going to be a 4WD tailshaft, which is the input into your transfer case.
3. If an NV4500 mates up to a 4BD1 or 2, I would suggest that route and several transfer cases are then options at that point. Make sure you fix the known issues with the 4500 before dropping it in. Call Greg at High Impact if you have questions.