There's 2 available that I can find - both on curse:
The first:
http://war.curse.com/downloads/war-addons/details/combatlog.aspx - appears to support groups and sync'ing group stats - from the readme:
GROUP DATA SYNC
===============
This option is still pretty experimental, so it is turned off by default.
In order to share data between players the mod will join a channel and post combat data to the channel periodically. There are still a few issues to work out, such as automatically turning off the chat filter for the channel used and automatically joining an appropriate channel (named after the group leader) as the player joins and leaves groups, as the leader changes, etc.
For now, the most reliable approach is to use the command "/cl sync <channel name>". Everyone that is going to share information will need to enter that command. Exiting the game or reloading the UI will cause you to leave the channel, so you will need to rejoin it.
Mousing over the "Group" heading on the CombatLog window will indicate what channel you are currently in and what number was assigned to it. The sync rate is currently set rather slow, at about 10-15 seconds between sends, the game has built in chat rate limiter which can be triggered fairly easily.
To turn off the chat sync function, use "/cl sync off". There is a "/cl sync auto" option, which will attempt to figure out who the party leader is and join a channel based on their name, but it's still VERY experimental and has known problems with warbands and scenarios so I would recommend not using it until it's perfected.
The second supports extracting the info to CSV - it should be pretty simple to wrap it into a spreadsheet for graphs or to write something.
If you think it's useful to have something for the Guild then I can knock up a web app - I've been looking for a project to try out a framework - so I'd be happy to work on it.
