Ya I just don't and have never gotten why every other country in the world makes just about every small truck with a diesel, just look on any over seas Craigslist for a Tacoma, Colorado, ranger etc. all have diesels.
Jeep came out with a diesel version of the Liberty a few years ago but stopped making them for some reason.
I've seen a lot of guys who do the cummins 4bt conversion, usually they get a hostess truck and pull the 4bt from them.
There is a company isuzudieselswapper.com that makes the adapter to bolt up a Isuzu from a NPR and drop it in to a 1/2 ton Chevy.
I think or hope dodge will offer a Manual, they offer or offered them in the 2500 , same thing w ford.
A few years ago there was word Ford was putting a small diesel in their Ford Ranger & it was sold in other countries but possible eventually being sold in the US.
Don't know why it never happened. EPA maybe said no deal, Maybe big oil squash that idea for them