Except for the fact that the cost will be completely and totally prohibitive (read outrageous), A 4 wheel drive with a lot of horsepower tends to tear up a lot of components, and there's a lot more to tear up in a 4x4, so they'd have to build everything tougher which would add to the cost even more. My 48 CJ-2A w/ 350 small block (previously had 327 vette engine) can tell you all kinds of stories about tearing up drive train components.
