1st:
You could set permisions for avatars.
For exsample, you could make a "Moderators only" avatar folder, and only the mods could use thoes avatar.
2nd:
You could set permisions for avatar hight and width.
For exsample, you could give members 60 pixel tall sigs, and moderators 100 pixel tall
sigs.
3rd:
When a member gets a certan number of post, they they get more abillitys, like editing.
You could set permisions for avatars.
For exsample, you could make a "Moderators only" avatar folder, and only the mods could use thoes avatar.

2nd:
You could set permisions for avatar hight and width.
For exsample, you could give members 60 pixel tall sigs, and moderators 100 pixel tall
sigs.
3rd:
When a member gets a certan number of post, they they get more abillitys, like editing.