I would say: very difficult.
I'd think you'd be better off compiling a list of 4WD vehicles and choosing from that. Unfortunately all the relatively light/non-truck ones I can think of are probably long gone (Tercel wagon, Honda Civic wagon, Subaru Loyale wagon, etc.)
Also we forgot to include this car on the list - probably the most complete DIY parallel hybrid (4WD) out there:
http://ecomodder.com/forum/showthrea...iero-9156.html