Yeah, Hemi might be good but too expensive and oddball for parts in Oz, it's bad enough just owning a Jeep
And does a JK need a 5.7 or 7 litre? I doubt it a good 5 litre would be plenty of grunt, going big means you can no longer use standard transmission, axles or CV's. The little 3.8 isn't that bad once it loosens up a bit of course a few more cubes would be nice and the sound of a sweet V8, but not all of us want that many horses to play with. I have no desire to bend my chassis into a pretzel.
Spending an extra $5k rebuilding and moding a LS1/2 with some smick parts maybe even a supercharger to suit a 4WD application instead of freight and import duties on a Hemi would probably produce similar results anyway being easier to get approved/insured and friendlier on the driveline.