This is an idea that came to me about a day ago. Everyone that starts off in the guild will start off as Rank 1 (this is what the "Job Rank" option is for). Rank 1 means you are new at your job and don't have experience. To raise your rank you must pay a fine (I need to get funds for the guild someway):

Rank 1: Free
Rank 2: 500 gold
Rank 3: 1000 gold

Ranks are necessary to qualify for harder missions...the higher the rank, the harder your mission.

Swordsman:
Rank 1: Woodenswordsman
Rank 2: Broadswordsman
Rank 3: Greatswordsman

Ninja:
Rank 1: Genin
Rank 2: Rogue Ninja
Rank 3: Coruppted Satoosa

Abyss Mage:
Rank 1: Apprentice
Rank 2: Dark Magician
Rank 3: Chaos Sorcerer

Light Mage:
Rank 1: Apprentice
Rank 2: Holy Magician
Rank 3: Enlightened One

Outlaw:
Rank 1: Common Thug
Rank 2: Sneaky b*****d
Rank 3: Phantom Thief

Pirate:
Rank 1: Cabin Boy
Rank 2: Captain
Rank 3: Pirate King

Ranger:
Rank 1: Whippersnapper
Rank 2: Whiplash
Rank 3: Whip Tamer

Guardian:
Rank 1: Protecter
Rank 2: Great Shield
Rank 3: Sanctuary

Gunner:
Rank 1: Lost Bullet
Rank 2: Quickshooter
Rank 3: Bulls-eye

Archer:
Rank 1: Bad Bow
Rank 2: Dead Aim
Rank 3: Sniper

Morpher:
Rank 1: Wet Puppy
Rank 2: Beast
Rank 3: Animal Fury

Fighter:
Rank 1: Sissy
Rank 2: Blackbelt
Rank 3: Man Killer

Adept:
Rank 1: Petty Psychic
Rank 2: Future Sight
Rank 3: Mind Destroyer

Musician:
Rank 1: Untalented
Rank 2: Heart Stealer
Rank 3: Sound Blaster

Bounty Hunter:
Rank 1: Scavenger
Rank 2: Head Hunter
Rank 3: Soul Recolecter