Your solution is an addon. Back in BC I used Ora2, which had a cool down frame to track who had a battle rez available. It has since been updated to Ora3. Since I only raid lead 10 mans these days I have no need for it and I'm sure there are other mods that help you track battle rez timers.
However this is the one I would recommend: http://www.wowinterface.com/download...4635-oRA3.html