I've finaly found some Pips(images) for the ranks. There are only 6 ranks, and they like this.
Rank - Posts Need.
1 - 0 Posts
2 - 100 Posts
3 - 500 Posts
4 - 1.500 Posts
5 - 5.000 Posts
6 - 10.000 Posts
And the Images will appear below your nickname.
I'll made custom Pips when I'll find decent chocobo images...
When I'll make custom Images, I'll make them so they will be 12 Ranks.
Enjoy