The foundation of combat is well under-way!
Combat is supported by an action queue - group members request to perform actions, which get put on a queue that the leader's session processes. If the leader isn't connected, there's no progress in combat. But, on the up side, only one person is editing the combat object, meaning there's no chance of an update getting lost.
Groups, for example, are a willy-nilly update process, which still has me a little worried that two members will override each other's moves if they're attempting to walk around a city at the same time. I can test that out at a later date.
I've updated the character sheet to require equipping/unequipping items to go through the combat queue if you're in combat, since swapping out a weapon is a move action and donning new armor is a full-round action. Body armor can't be changed during combat. The character sheet was a good first step before moving on to actual combat options (like round progression), as it will probably be the most difficult thing the combat queue needs to handle.
So, no code update today, but progress is being made!