When you start looking at engine swaps try and get a 2wd transmission with a rwd vehicle. That way you can just modify the drive shaft to go into the divorced transfer case.
Make sure you check engine size and the length of the drivetrain. There isn't a whole lot that will fit in the engine bay. Some people have bee doing Nissan Diesel swaps to some success, I think a Isuzu swap would be a lot of fun.
