I don't think theirs any way possible a 5.9 would fit due to both the weight and heigth of the engine. It's a HUGE, HEAVY engine! LOL. You "might" be able to fit a 4BT cummins in there though and they are pretty bada$$ engines. And as far as the "hemi" thing goes pretty much any modern OHC engine has a "hemi" chamber in them. It was high tech stuff back in the 60's but nowdays it's just a gimmick because when people hear hemi they think a firebreathing 426 hemi making waaaaaay over it's 400 something hp it was rated at.
2007 JK unlimited rubicon, red rock crystal pearlcoat, rc 2.5" spacer lift, 35x12.50 goodyear mtr/k mounted on black 15x8" mb72's. (Mine)
2005 WK Limited 4.7, QTII, Midnight blue pearlcoat. (Hers)