The paintless dent repair guys can work wonders - even on keyed paint work. Have a look at their website, and give them a call - they'll come out and give you a free quote, and tell you if its beyond their scope. But using touch up paint, and cutting and polishing, key marks can be repaired without a respray.
One website : http://www.chipsaway.com.au/
Click on the Before and After button on the left.