Attached Link: http://dmi.chez-alice.fr/models1.html

I don't know of any in a store, but here is a site with tons of free cars. Maybe they have one there?

EDIT: Actually, yes there is one there. It's got a police texture, but you can easily change that.

It's for "Lightwave", but that can be converted to an .obj file easily enough with the help of "Poseray"

http://dmi.chez-alice.fr/modelsrescue1.html

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi