I don't know how to write greasemonkey scripts, but it would be cool if someone wrote one, or the CC admins added a frag count.
Basically it would count every player you personally eliminated as 1 point. Your batting average would be: (Frag Ct / number of players). For instance a 6-player game you could be 1-5 of 5. Team games you'd only get credit for the other team's players.
Another way to score it would be +/-, where you get +1 point for a frag and -1 when you get eliminated. All positive scores would represent above average players.