your idea is the best i have read so far. one sticky to each moderator. increase the stickies to 6 or decrease the mods to 4. when a moderator resigns or is removed, so is the sticky if they had one posted.
one other idea, get rid of the iboxes on stock specific boards. the first thing i do when i go to a stock specific board, is shut the ibox. traders are supposed to do their own dd, last i knew.