Hello!
I've been out of the RC world for around 5 years, but I'm back, and I've been studying the Vintage Traxxas models. I've got discontinued parts lists for them all if anyone is interested. Anyway, I've discovered a very interesting source for new Image .12 parts, from the original manufacturer. To read the following, use my explanation here.

Discontinued Traxxas part number=original manufacturer's part number.

These are parts that are identical to the discontinued Traxxas parts.
3239=12124 Stud & nut, carburetor attachment
3239=12118 Nut, carburetor attachment
3241=12845 O-ring, idle mixture needle screw
3242=12811 Nut, throttle lever
3243=12812 Lever, throttle
3244=12813 Rotor (carburetor barrel)
3245=91814 Spring, rotor
3247=12816 O-ring (I can't be sure of the color, mine was missing)
3248=12817K Needle seat, idle mixture (I can't be sure, mine was broken and the internal piece was gone)
3249=12818 Nuts, seat securing (2)
3254=12832 Screw, idle speed adjust (w/ nut)
3254=12837 Screw, throttle stop (w/ spring)
3209=12102 Engine backplate (Eliminates recoil starter) (Requires electric starter) (I can't be sure, I've never seen a Traxxas one)
3213=12111 Gasket, back plate
3221=12110 Bearing, crankshaft (rear) (I recommend an upgrade ceramic bearing)
3222=12101 Crankcase (w/o bearings) (says ASP on the front instead of IMAGE)
3223=12109 Bearing, crankshaft (front) (I recommend an upgrade ceramic bearing)
3225=12203K Sleeve, cylinder/ piston (matched)
3226=12213K Wrist pin/ G-spring retainer (1)

These are parts that will work on the Image .12, but are not identical to the originals.
3240=12804K Carburetor assembly
3246=12815K Body, carb
3250=12861K Needle assembly, high-speed
3250=12819K Nipple/ gasket
3250=12848K Needle valve body
3251=12833K Ratchet spring, high-speed needle

These are parts that will only work with each other, not the originals.
3270=12522K Assembled starter
3274=12506K Backplate (uses 2.5x8mm cap screws, 12518)
3275=12516K Starter shaft
3211=12502K Bearing, one-way starter/ starter engagement housing

I'm still researching if the crank and cylinder head are correct. I'll post them if they are in the near future.

You can get these parts through here. The prices need to be converted from CZK Czech Koruna to your currency, but the parts are pretty cheap.

Hope this helps!