When that time comes i bet we'll be hearing about how they've expanded and how it will impact the company and the vehicles VM engines will go in.Technically you are right, its made by vm motrori of Italy which is/was owned by FIAT so now its technically all in house,
"The 3.0-liter EcoDiesel engine is manufactured by Fiat Group Automobiles' VM Motori in Cento, Italy. Chrysler Group has utilized VM Motori diesel engines since 1992."
They pretty much make as many of these as they can, but vm motori also has to make a crap ton of other engines for the euro market as I understand it. They also had no idea the engine was going to be such a huge hit (how many of you knew it was in the grand cherokee before, for over a year, it was ever announced for the 1500?) so you can imagine it will take some time for them to both figure out how many to build and then make that happen.