Back around XMas I was wandering a Dollar store and saw a cheap kit to make a car look like one of Santa's reindder, it had antlers you could put on the roof, a red nose for the front.
I thought, why not something like that for something more furry. A tail you can attach to your trunk, some ears with a magnetic base to put on the roof. Not sure if mods like this would survive highway speeds, but should be fun when parking at a convention, right?
Maybe a furry cover for side mirrors, to be ears.
I know I dont have the automotive or fursuit making skills to do this on my own, but if anyone else with more talent wants to give it a try, please send photos.
Link
Trianine
Magnets are used to add delivery signs on the roofs of cars. And large vinyl advertisements. It should be doable for other things.