Why not just go with the same coin theme as the existing rank icons, but in a different color that indicates a white-hat look & feel, such as green? All of these ideas are great, but most of the suggested icons do not fit the current look and feel of what the forums have to offer.

Here's an example:



The coin gif is already in use, which means it's royalty-free (I'm assuming), and it's not hard to re-color the existing image that you're already using. The look is uniform, and it matches well with the existing feel of the forums.

I modified the milestones a bit, and maybe you could add a half-coin accent (for the fifth coin) for anyone that submits over 10,000 good reports (to match the existing rank icons).

Sometimes the most subtle changes/additions are the most effective ones. Thoughts?