Just my 2cents, but I see a lot of guys rationalizing some type of re-vinning, whether to save an old car, or whatever.
The fact of the matter is, its illegal. plain and simple, regardless of the reason. It's a federal crime, with real consequences.
As to replacing every piece of the car around a VIN, thats wrong too. I'm sorry, but if a Hemi Cuda convertible gets squashed, or rusted to the point of no return, its not ok to resurrect it by using another vehicle. At that point, all you own is a title and a VIN tag. The car is gone. That's the way it is supposed to stay.