We've experimented in my game with a "combat coordinator." That's a player (Vic) whose job it is to keep the other players (the not-Vics) organized for combat. He calls out the turn order, makes sure people are ready, etc.
It's worked out, kind of. Sort of. Well sometimes, not so well other times.
We've been debating a "caller" like position for someone to organize the group. We've been playing with 7-10 people, and a 10-player session plus 4-5 NPCs isn't easy for the GM even with people on their toes.
One of my players (J~) has taken on the role of record-keeper of loot and purchased items, and what items were found and lost in the dungeon (useful, because my players don't often update me on what their fallen, lost compatriots carried when they fell.)
We've debated a rotating leader position, with that person getting final say and getting to set the scope of the session's delve.
This guy has taken all of that to a very, very detailed level of analysis.
Barker's Rolodex: Record Keeping for a Long Campaign
I'm impressed, and it very neatly explains how and why to do those things we've been doing or debating doing. Since it agrees with my ideas, by the Law of Confirmation Bias, I hereby declare his post to be helpful, accurate, true, and well worth reading. Check it out . . . I think we might be able to use some of the suggestions to fill out our ideas.