After thinking of doing an OBDII/CA SMOG compliant swap in to the Zuk, I found the requirements crazy.
What ever engine you pick, make sure it's legal to put in before you do anything. Aka, in CA SMOG rules, a truck engine can not be installed in non-truck, and vice-a-versa; if you put a newer engine in, it has to come with the smog equipment for that engine, not the vehicle. I'm sure AZ has a book somewhere that says what's legal and what's not for their smog.. or call up the smog refs and ask them, but do realize they can say one thing and it could still fail.
If you do an OBD-II based swap, get a wrecked vehicle and strip for the emissions parts. You will need everything OBDII certified.. That's the engine, transmission, transfer case, speed sensors, vent/vapor system, gas tank, and cats. OBD-1/Pre-95's are much more easier if you stay away from the OBD-II stuff.
You otherwise, I say a Ford Godzilla/7.3 gas engine and some 8 speed transmission with transfer case. You could put it in 4x4, lock the axles, and smoke all 4 tires..