Found this on Wikipedia. Hope it may be useful for anyone researching on the V12 powerplant.

List of Post-1945 V12 Production Road Cars (Alphabetical by make, sub-sorted by year of introduction):

• Aston Martin DB7 Vantage
• Aston Martin Vanquish
• Aston Martin DB AR1
• Aston Martin DB9
• Aston Martin DBS
• B Engineering Edonis
• BMW 750i/750iL/760i/760Li
• BMW 850i/Ci/CSi
• Bugatti EB110

• Daimler Double Six
• Ferrari 166
• Ferrari 195
• Ferrari 212
• Ferrari 340/342
• Ferrari 375/375 America
• Ferrari 250
• Ferrari 410 Superamerica
• Ferrari 400 Superamerica
• Ferrari 275
• Ferrari 330
• Ferrari 500 Superfast
• Ferrari 365 California Spider
• Ferrari 365 GT 2+2
• Ferrari 365 GTC/GTS
• Ferrari 365 GTB/4 & 365 GTS/4 (Daytona)
• Ferrari 365 GTC/4
• Ferrari 365 GT4 2+2
• Ferrari 400i/412i
• Ferrari Testarossa
• Ferrari 456
• Ferrari F50
• Ferrari 550 Maranello/Barchetta Pininfarina
• Ferrari 575M Maranello/Superamerica
• Ferrari Enzo
• Ferrari 612 Scaglietti
• Ferrari FXX
• Ferrari 599 GTB Fiorano
• Jaguar E-Type
• Jaguar XJ-S
• Jaguar XJ12 & XJ12C
• Jaguar XJR15
• Lamborghini 350GT
• Lamborghini 400GT
• Lamborghini Islero
• Lamborghini Miura
• Lamborghini Espada
• Lamborghini Jarama
• Lamborghini Countach
• Lamborghini Diablo
• Lamborghini Murcielago
• Lamborghini Reventon
• Lincoln Continental
• Lincoln-Zephyr
• Lister Storm
• Lotec Sirius
• Maserati MC12
• Maybach 57 and 62
• McLaren F1
• Mega Track
• Mercedes-Benz CL600/CL63 AMG (W215)/CL65 AMG
• Mercedes-Benz S600/S63 AMG (W220)/S65 AMG
• Mercedes-Benz SL600/SL65 AMG/SL73AMG (R129)
• Mercedes-Benz CLK GTR
• Pagani Zonda
• Panther De Ville
• Panther J72
• Rolls-Royce Silver Seraph
• Rolls-Royce Park Ward
• Rolls-Royce Phantom
• Rolls-Royce Phantom Drophead Coupé
• Toyota Century
• Vector M12

See also: W12 engine

Sport-utilities:

• Audi Q7 (a turbodiesel engine)
• Lamborghini LM002 SUV

Concept cars:

• Aston Martin One-77
• Aston Martin Rapide
• BMW Nazca M12 (a concept by Pininfarina)
• BMW CS Concept
• Cadillac Cien
• Laraki Fulgura
• Isdera Isdera Commendatore 112i
• Lincoln Continental (2002 concept)
• Méga Monte Carlo
• Monte Carlo GTB
• Peugeot 907 (Peugeot’s first V12, 2004)
• TVR Cerbera Speed Twelve (never entered production)
• Volga V12 Coupe (a one-off custom rebody)
• Yamaha OX99-11

Brabus also sell the Mercedes-Benz E-Class and CLS with a V12.

A V12 engine is a V engine with 12 cylinders mounted on the crankcase in two banks of six cylinders, usually at a 60° angle to each other, but in some cases at a wider or narrower angle, with all 12 pistons driving a common crankshaft.^[1]

Since each cylinder bank is essentially a straight-6, this configuration has perfect primary and secondary balance no matter which V angle is used and therefore needs no balance shafts. A V12 with two banks of six cylinders angled at 60°, 120°, or 180° from each other has even firing with power pulses delivered twice as often per revolution as, and is smoother than a straight-6 because there is always even positive net torque output with little variation. This allows for great refinement in a luxury car. In a racing car, the rotating parts can be made much lighter and thus more responsive, since there is no need to use counterweights on the crankshaft as is needed in a 90° V8 and less need for the inertial mass in a flywheel to smooth out the power delivery. In a large displacement, heavy-duty engine, a V12 can run slower than smaller engines, prolonging engine life.

http://en.wikipedia.org/wiki/V12