It's a bit like the Skoda ad for the Fabia, where they make the car out of cake - but that was real. They had a team of model makers and bakers working together on it. There was a really interesting article in Creative Review about it, talking to the guy who got the whole thing together. I can't find that online, but I have found a link that lists the ingredients used to make it!
On the subject of car ads I've got to mention the Honda ads, which are consistently great. I found a link to the one with all the parts, like a giant version of the 'Mousetrap' boardgame, which is still fascinating (and it was all 'real', no animation or editing). Take a look.
