This is currently a work in progress for version 2.0 of this plugin. There is a lot of work to do still, but I decided to make it public and to see what people think. I am putting this plugin on top of my plugin to-do list, so feedback now will be a good thing.
Here is a list of features requested on the v1.0 thread for this version, with a Yes for being included in the current code and No for not included yet.
Settings: Core
List PvP'd Players: Yes
Cooldown (command): Yes
Cooldown (attack): Yes
PvP activation announcement: Yes
Permissions: No
KillSwitch: Yes
Change default setting: Yes
Localization: No
Toggle startup message: Yes
Hooks: No
Admin Override: Yes
MultiWorld Support: No (not sure what, though)
Duel: Yes
Adjust other's settings: Yes