For those that found the hood as a heatsink idea interesting-
Source
The following is a partial list of manufacturers who use aluminum body panels.
Acura – NSX (all), RL (hood, decklid, fenders and trunk)
Aston Martin – Vanquish (body panels), DB9 (hood)
BMW– Z8 & 7 series (body panels), 6 Series (hood, doors, body panels)
Buick – LeSabre (hood), Park Avenue (hood), Rendezvous (liftgate)
Cadillac – CTS (hood), Deville (hood), Escalade (liftgate), Seville (hood)
Chevrolet – Suburban (liftgate), Tahoe (liftgate), Venture (hood)
Chrysler– Concorde, LHS, Pacifica (hoods)
Ferrari – 360 Modena (body panels)
Ford – Expedition (hood & liftgate), Explorer (hood and fenders), F-150 (hood), Lincoln Navigator (hood & liftgate), Lincoln LS (hood, fender & trunk lid), Ranger (hood), Lincoln Town Car (hood), GT (body panels), Mustang GT (hood)
GM – Yukon, Yukon XL (liftgates)
Honda – S2000 (hood), Insight (body panels)
Infiniti – Q (hood & trunk lid) I (hood & trunk lid)
Jaguar – XJ, S-type (hood)
Lancer – XJ, S-type (hood), Evolution VIII (roof)
Lexus – SC430 (hood)
Lotus – Elise Sport 190 (body panels)
Mercedes – CL500, SL500
Mercury – Mountaineer
Nissan – Altima, Maxima (hoods & trunk lids)
Oldsmobile – Aurora (hood & trunk lid), Silhouette (hood)
Opel – Speedster (body panels)
Panoz – Roadster (body panels)
Peugeot – 407 (hood)
Porsche – Cayenne (hood), 911 (hood)
Plymouth – Prowler (hood, doors & trunk lid)
Pontiac – Bonneville, Montana (hoods)
Range Rover/Land Rover – hoods, doors, side panels
Saab – 9-2X (hood)
Subaru – 9-2X (hood), GT (hood), Legacy (hood, bumpers, sunroof)
Volvo – (hoods & trunk lids)