Instead of switching back and forth between GM's, how's about someone create a new account, start up an alt, move the alt into the guild, and have that alt take the GM position? You higher ups can private message each other with the account info and log into it whenever necessary. This way, we're never without a GM. We won't have to wait for someone to come online to hire/fire mercs. If something needs to be brought to the guilds attention right away via Notice, it will be.
Anyway, its just a suggestion and if you do go thru with it, I hope you'll share the info with those you think/know won't be the downfall of the guild. I actually like this guild, its small and yet we're still strong enough to go out as a whole and kick ass. =)