Ammobag Hider is a basic mod that Whenever all of your bags are opened keeps your ammunition bags closed. (You can still open the Ammo Bags manually.) This works together with the key binding which is used to open all bags (default is Shift - B) or with other Add-Ons which opens all bags (like AuctionIt or Baggins).
I should have the one for quivers done in a day or two. Eventually for Wotlk i will be combining these (shardbag, ammobag, and quiver Hiders) into one mod with load on demand based on what class you are and what you have equipped in your bag slots.