A lot of good fabricators, backyard or professional, could get the Isuzu in place. But most installers have issues is the control system... as is electronic, computers, sensors and wiring. Some earlier versions of diesel engines are mechanically controlled so are a LOT simpler for swaps... just less efficient than the computer controlled versions. (What type are your spare engines?)
How much physical size difference is there between the original engine and the Isuzu? If much longer, you might have radiator issues, if much wider, exhaust or steering linkage issues.
I am assuming you are using the transmission from the Isuzu, avoiding the bell housing issues. Does the trans have a transfer case? Is the front drive shaft on the right or the left? Does the trans need a computer and wiring? Interfacing with the engine computer is sometimes an issue. (Another reason to use the engine and trans from the same application.... if possible.)
Something I have been looking at is the 4 speed autos (A44DE) used in the 4 door TracKicks. The basic transmission is used in MANY different rigs, some are NOT computer controlled. It also has a separate bell housing. You might find a bell housing that will mate to your engine and this trans. Then you should be able to us the same transfer case used in the 4 door TracKick. You could select the actual transmission on if you want computer or not. Not sure what you would need to do about automatic shift points to work with a diesel engine's torque curves. Just go with a manual???
Bottom line, you should be able to get the Isuzu in place. getting it work, might be an issue, depending on your capabilities. (Or the capabilities you can hire.)
OBTW: I just noticed the "2wd" but left the transfer case issues in for future readers with 4x4's.
