A so-called 'rat rod' may be a vehicle suitable for a ZCL practitioner.
A rat rod is a hot rod designed - not for show (as is the usual case) - but to be used on the street.  A rat rod need not be 'hot' however, (though they usually are) with an oversize, gas wasting, high horsepower engine. (A ZCL practitioner could install a modest efficient engine in a rat rod).
Rat rods are very broadly defined with as many shapes, sizes, and types as the creators of these machines can come up with.
A rat rod is generally a homemade, (or owner built) automobile, usually created from the thrown together components of several (or even many) other vehicles. Old and new components may be mixed together.  Ford, Chevy, Chrysler, and just about any other car parts made may be mixed together (and often are).  A Ford frame, wheels, steering suspension (rolling chassis) may be combined with a Chevy body and engine.
Rusty body parts are okay, even favored.  The patina of rust is an aesthetic statement in the rat rod community.  Rust can be beautiful.  Rat rodders tend towards disdain for conventional ideas about aesthetics in cars.  And, they are in (what I would call) technological rebellion against modern cars with their complexity, computers  gadgets, spaghetti of wires, and plastic trim.  They favor clarity and simplicity in design and construction - which helps them build their creations more easily  - since they usually build them themselves.
Some (many in fact) rat rod builders claim to have spent  a thousand or perhaps 2,000 dollars on their creations, using old parts, junkyard parts, parts off wrecked cars (perhaps salvaging a good engine off a recent wreck). The design and layout of rat rod -drive train, body, etc. generally is chosen to make the rod easier for the owner to build.  For example, rear wheel drive is favored over front wheel drive (which has greater complexity and more parts, and more complicated parts - such as CV joints)
And, owner built usually means the owner can repair it.  A (relatively) simple, accessible engine and all other systems allows the owner operator to more easily repair and maintain a rat rod vs a conventional automobile.

Owner built, low cost, simple, easy to fix these are what anyone attempting ZCL is looking for in a vehicle.

Now, to adapt the rat rod concept to a ZC lifestyle I suggest these changes.
frame and body:
Generally rat rods have full underbody frames (like a pick up truck) rather than 'unibodys' (like modern cars) so the engine, mounted on the frame and not covered by fenders/quarterpanels is exposed, right there in your face, often without an engine cover which means everything is accessible, easy to get to - easier to repair vs conventional cars (with their engine squeezed and packed into the unibody and therefore hard to work on).
The frame, or better, rolling chassis (with wheels, suspension, brakes, steering) of a Chevy S10 or Ford Ranger pickup would be a good foundation for a rat rod.
aerodynamics (streamlining):
For streamlining and better mileage I would add panels - easily removable panels around the engine.  And, I would favor a body with some streamlining - late 1930s, 1940s or later over earlier cars, (that had flat plate windshields for example). I favor the two plate 'V' shaped windshield of the late 40s early 50s because they are cheap to buy and simple to install compared to later compound curved massive one piece windshields.  Yet these V windshields have pretty good aerodynamics.
As a more aerodynamic alternative I favor a one piece windshield of polycarbonate plastic formed in a 'conic section' - no complex compound curves -  but this will be more complex, expensive, and harder to install than the V windshield. A polycarb windshield could add tremendous structural strength to the upper body of a rat rod. Glass adds almost none.
Install a modest, cheap simple engine, not a massive engine to use in racing.
For an engine I favor the 'straight 6' (over the more usual V 8 favored by rat rod builders).  The 'straight 6' or inline 6 cylinder engine is naturally 'balanced' as it runs, requiring no balancing flywheel as is needed by 4 cylinder engines and by V8 or V. The V6 is the common engine in automobiles today, but now you have two heads, two head gaskets, two valve covers with gaskets, two exhaust and intake manifolds (with more gaskets), and greater complexity to manufacture, maintain and repair.  Gaskets, unfortunately as engines get old, tend to fail and leak causing a host of additional problems.  Gaskets are an expensive job at an auto shop. Gaskets in a rat rod with an accessible engine may be easier for the owner to replace - but still, it is not an easy job.  A straight 6 engine has many fewer gaskets.
A straight 6 engine gently used can last hundreds of thousands of miles - and some with careful owners  - have.
fuel system:
Model T and Model A automobiles had gravity feed fuel systems, no fuel pump, no pressurized fuel lines required.  Wonderful simplicity.  And both cars could run on ethanol (grain alcohol) by adjusting engine timing using a manually controlled lever in the cab. (Dual fuel capability without complex expensive technology).  A rat rod could be designed to make gravity feed possible (but still safe).  Specifically a gas tank can be installed in the short (often very short) truck bed behind the cab. This configuration has been used on many rat rods. The tank sits higher than the carburetor of the engine and so gravity feed  - as a fuel line from tank to the carburetor is possible.
The gas tanks of these rods are steel cylinders that are far stronger than ordinary gas tanks under conventional cars.
Fuel injection is standard today, but complex, with computer required and multiple sensors ready to fail and hard to diagnose, or even access in some cars.  A carburetor properly designed, maintained, and operated can be far simpler and cheaper and just as efficient (in most circumstances). A manual choke can be simpler and work better than the complex automatic chokes used on most cars for many years before fuel injection.
drive train:
Rear wheel drive with universal joints, drive shaft, differential, manual transmission, stick shift, (3 or 4 speed or for efficiency- even more)  is simplest, cheapest, and easiest to fix.  The automatic transmission is so complex car repair books for owners do not explain how to repair it, but only how to remove it so you can take it to a shop.  Very complex and expensive.  Rat rods almost always use stick shift on the floor.  (Shift on the floor is simpler, with less to go wrong, and is easier to repair than shift on the steering column).
The clutch wears out on stick shift transmissions, but is replacement is possible by the owner, not simple because the transmission must be removed to get to the clutch, but it is usually the only repair needed on a manual transmission (unless you abuse your transmission as you may do if you race) - and the only difficult part about the job is lowering the transmission once the bolts are off, and raising it up again into position to put it back on. Someday a genius will design a manual transmission where the clutch can be changed WITHOUT removing the transmission.
I favor simple tabs on windows that you slide back and forward or up and down by hand.  Hand cranks and lever assemblies in the doors are a pain to make work right when they go bad - especially in old rusty rad rod style bodies. And of course electric power windows are right out.
The wiring diagrams of the old Model T and even the electric start Model A are wonders of simplicity and clarity compared to modern cars with spaghetti mazes of wires and many pages of wiring pages in auto repair books.  Power windows, locks, gauges, various accessories, lights, fuel injection sensors, anti lock brake wires etc, etc.  cause this.  A rat rod need not have most of this saving you all the time and trouble of messing with it.
A fuel gauge on a rat rod (on a tank in the rear bed) may consist of a dip stick on the fuel tank filler cap.
Power steering is another unnecessary complexity on a rat rod.  On a rat rod, if the vehicle is kept lightweight, manual steering is possible.  Thinner tires, bigger steering wheel (for leverage) also may make manual steering easier.  The extra arm exercise of manual steering could be welcomed as a chance for exercise while doing something useful.  Power steering has plenty that can go wrong: tanks, tubes and joints that can leak,  gearing that can fail, etc. Like manual transmission, manual steering greatly reduces possible hits to your wallet while living ZC.

Hybrid Electric Rat Rod:
See my discussion on 'Hybrid Electric Car' in this web site for more on this concept.  Here, I want to add that discussion:  instead of a conventional internal combustion engine powertrain (such as the straight 6 configuration suggested above) a series hybrid electric powertrain could be installed in a rat rod. Where the radiator and front half of the straight 6 would go on the frame rail, a generator (with internal combustion engine to turn the generator) would be placed.  Attached to the manual transmission (and where the back half of the straight 6 engine would go on the frame rail) - add an electric motor driving the rear wheels.
Batteries could be place in the back in the short (very short) truck bed of the rat rod.
6 batteries weighing 400 pounds are suggested.  The weight would assure good traction over the rear wheels in rain or snow, (if the tires are right).
One final consideration: The transmission of an electric vehicle such as this DOES NOT REQUIRE A CLUTCH or if used, the clutch suffers very little wear so it may last 200,000 miles.  The clutch can be left out of the drive train yet the vehicle can still be shifted (the vehicle can be left in 2nd gear most of the time including at startup because electric motors have high starting torque compared to internal combustion engines).
Thus the cost and difficulty of replacing the clutch can be eliminated.