How about... THE SUMMONER GUILD!!!!
Probably a very terrible idea, but it'd give the option of another magic primary guild if you don't want to be the warmie everyone else is, and don't want to be a cleric. Summoner's would be gifted with the power and mastery of not elements, but summoning extremely powerful beings. Just throwing out an idea, I'm pretty sure there's too many flaws in this one, but I couldn't help imagining something like this... especially when one of my favorite games has summoners in it. :)