Although you dont want to paint it, I'd say try Plasti dip, although it comes in like 2 colors (Black and White) the stuff goes on easy, and best part of theres overspray, just peel it off like a sticker. Check out youtube videos about plasti dip, its crazy durable against paint and weather.
People have actually plastidip'd their cars and have said that it's held out for a very long time.