I run a small vinyl sign business out of my house to keep me busy on the weekends. I would be able to make glow in the dark vinyl stickers which would be pre-cut rings to fit perfectly around the key slot if there was enough interest. I haven't priced it out yet, but I assume they would only be a few dollars each and I could mail them in a normal envelope so there would be no shipping. The key slot doesn't bother me, so I wouldn't put one on my car, but if anyone is interested let me know, and I'll do a little more research and possibly production if I could make them cheap enough. That said I could make just about anything as a vinyl sticker, so let me know if you have any other cool ideas.