The interdisiplinarian guild. You come up to a clerk or something and register yourself as a(n) "INSERT PROFESSION NAME HERE". You create your own skill reqs. Around 30 ranks per circle to start out with. 10 go to primary skills, 10 to secondary, and 10 to tert. skills.

So, say you want to be an army archer. Ranger sounds good but you have no desire to chase squirls around in the bush but you still wanna be that army archer. You set up your own professions. You set up your own circle reqs maybe something like this....

PRIMARY
Longbow - 5 ranks
shortbow - 5 ranks

SECONDARY
Mech lore - 3 ranks
Foraging - 3 ranks
Evasion - 2
ME - 2

TERT
Armor - 2
Parry - 2
Hide - 2
Stalk - 2
Swim - 1
Climb -1

No more than 5 ranks per skill. You only get the primary "skill set" bonus on those individual skills not on the actual whole skillset. You may choose HE as a primary skill but if you don't have ME on your list you learn it at the same rate as any other novice noob. The ease of making your own skill reqs is offset by the fact you have no abilities to gain.

I do think there is a limited way magic professions could be played. Gaining spells would happen only every 5 to 10 circles and they are "purchased" off an RP'ed blackmarket. When you choose "primary magic" in your skill reqs you have to choose which mana type of primary magic. Possibly "some" guild abilities could be put into that system but again, only every 5 to 10 circles and probably you would have to be 10 or more circles above what is normally required to gain them.

Another example: You want to play an assasign but common pickpocketting is well below your station in life. And you'd like to throw in a little deceptive magic. You would have hiding, stalking, and a weapon in the primary. Lunar magic in the secondary and you choose hypnotize as your first spell in order to confuse your target before doing em in. Maybe choose some instrument or other random tert skills to form a cover ID for your hitman for hire business.

So, someone who just doesn't like any of the guilds but doesn't like being stuck as a commoner can advance, gain tdps, and have something to do with no one but themselves to blaim for that 1 more rank of teaching before the next circle.