As long as you could keep the inverter free of water and the light from extreme vibration I can see why this wouldn't work. I was thinking that a white CC would make a great underhood light. Also you could eaisly mount them in the footwells or under the seats if that was the effect you were looking for.
There cheap enough so even if it didn't work in the car you could always use it as a case light for your PC.
I'm not into neon lights but I have seen some members rides with them on. However, mounting those neon lights externally is not allow here where I live. I have seen them mounted for the subs and amps and they look good.