Actually,
I am paying Gardner to make one this weekend, so it is in progress I guess, but it is quite a bit more in depth than just referrals.
It will give points to users as follows:
10 pts for a referral
5 pts for a review/photo
1 pt for a post/reply
At least, I think that's how I told him
Points will be displayed on a page in order of top point holders, as well as number of points being displayed under each user's username.