You could make your own with
1) clip art
2) avery office products
3) COLOR LASER PRINTER
This would work very well with most products. I'm a bit concerned about the wear and tear a sticker would see on the back of a car. I wonder if something could be done to laminate it. I don't know how that world work with it having a sticky backside.
The other thought...keep your eyes open on ebay. Something might turn up.