So I was looking through Rigger 3 Revised for something, when I got the sudden and terrible idea of a vehicle that could alternate between two different chassis.

Yes, I thought about Transformers.

Could it work? Would it work? Should it work? (The answer to that last one is "No.")

Chassis: No
Appearance: Yes

having the Chassis be made out of smart materials and also containing photovoltic paint you could change both the model of the car and paint scheme.

For example you could shift between alternative models of Ford americar and it's equivalent of competing models.

You can change the chassis, obviously, but a properly designed chassis with hydrolics and smark materials should be able to switch between multiple configurations. Its nature would be obvious to anyone examining it closely, of course, but there is no good reason why you can't have an absurdly expensive and slightly unreliable cr that transforms into a giant anthroform.