Multilevel Sub-Forums

[Cerberus]

What i would like is a plugin that allows Multilevel Sub-Forums
What i think it would look like:

General Forums
|_Level_1a
|       |_Level_2a
|               |_Level_3a
|       |_Level_2b
|_Level_1b
|       |_Level_2a
|...

Instead of
General Forums
  Level_1a
    Sub-forums: Level_2a and Level_2b
  Level_1b
    Sub-forums: Level_2a