American Model Builders (aka LASERkit) sells laser cut acrylic "car sides". Said sides are designed to be mounted to pre-existing passenger car bodies (either American Ltd passenger car "core" kits, or mass-manufactured cars from the likes of Kato, Con-Cor and Bachmann). AMB's catalog is extensive, covering numerous different roads and car styles. And no, I'm not going to try to cover them all here. If you're interested, I suggest visiting their website - American Model Builders