I wonder if this is the right place, but I think it's close enough, anyway~:

I had an idea floating in my head for a long while about adapting a Final Fantasy setting into d20 rules and making it a table top RPG. The setting will use the Ivalice setting set out by Final Fantasy Tactics, Tactics Advance, A2, and XII. It's got a lot of fluff already (special thanks goes to FFXII's bestiary and plethora of Side quests), and several games all taking place in the land of Ivalice.

I've also been wondering to myself if the Job System could be incorporated into the d20 system? Being able to change jobs on the fly is fun, but I haven't figure out anything with that yet. The races were pretty easy to relate to the basic fantasy races, so let me list them here.

Hume <-> Human (of course, they're one and the same)
Viera <-> Elf
Bangaa <-> Dwarf
Moogle <-> Gnomes
Nu Mou <-> Tiefling? (Not sure, just my best guess.)
Seeq <-> Orc/Half Orc
Gria <-> Dragonkin (or however it's listed)

So that's what I've gotten thought out so far. Has anyone else had a similar thought, or has my idea already been tried/produced?

Never really played Dungeons and dragons but this sounds pretty interesting idea. Maybe I can help you somehow if I can..

At the moment, I'm open for a discussion, I have no actual plans to make this actually happen until I get some experience with pen and paper RPGs. The idea is to create a Final Fantasy XII/Tactics/Tactics Advance/A2 setting adapted to the d20 rule and playable with pen and paper. Fortunately, I am involved with a Pathfinders game group, so I have a chance to not only study, but experience how the d20 system works.

I've played pen & paper RPGs for decades.  The bulk of that time has been spent GMing.  While I HAVE spent some of my time playing in pre-written campaign worlds, I've actually spent the bulk of my time playing in worlds of my own creation.  (You name it, I've likely played it.  Right now, our gaming group spends the bulk of our time playing Pathfinder/D&D3.5, with the occasional weekend spent playing either Star Wars WEG, Classic World of Darkness, or Battletech.)

My current campaign involves a world that has spent nearly a thousand years trying to find its way out of the dark ages that the people who lived there accidentally brought upon themselves.  After a thousand years of servitude to their undead masters, the people of the world (Specifically the player characters) manage to shuck the shackles of slavery, and in doing so, unleash the ancient evils of the world (Since I know at least one player has a profile on this forum, I'll stop there.  But needless to say, at this point, the player characters are dealing with the repercussions of their own actions, . . . )

That said, I would suggest that you start by figuring out what your Final Fantasy world has in common with the base rules (Whether you are using D&D, Pathfinder, or some other D20 rule set.  Keep in mind that even if your rule sets don't always match, much of the information or advice from different publishers can still be useful  Pathfinder & D&D 3.5 require very little effort to interchange).  You'll find that a large portion of that information will be the same and that the bulk of what you need to work on will be cosmetic in nature. 

Using Pathfinder's Advanced Race Guide (Or something similar) will provide you with some guidelines for changing and/or creating your own races to fit your campaign.

There are also several "Ultimate Campaign" style books out there that may be of some help.  I've read a lot of them, and I've only found two of them that are really worth mentioning:  Pathfinder: Ultimate Campaign, and the Ultimate Game Designer's Companion.  Also, the Legends & Lairs: Sorcery & Steam book is an excellent resource for creating settings that deal with a blend of magic and steampunk.

Printing off some artwork can help give the feel of your locations, especially if you are trying to use existing places for setting.  And just as important, finding some Final Fantasy soundtracks or Final Fantasy inspired music to play softly in the background during gaming will contribute heavily towards setting the mood/feel for your game.

Job System.  I'm not really sure how well this would work.  On the surface, the simple act of multi-classing a character may be enough for most players.  But if you are looking into doing more than that, things could get REALLY complicated FAST.

The most important things to keep in mind:
-Keep a list of the changes you make, and make that list readily available to your players.
-K.I.S.S. Keep It Simple Stupid.  Keep your changes as simple as you are able.  Complicated changes annoy players
-Do your homework.  Look up information for anything specific you want to cover so that you get the lore, abilities, people, and/or other information right.

I'm more than happy to act as a sounding board for ideas if you are interested. 

I'll be looking forward to seeing what you come up with!  You have a neat idea, you should run with it!

PS :   I Bing'ed "Final Fantasy D20 once I typed the above.  The first two links look interesting ( I just opened the websites, I didn't do more than browse the sites for a few seconds, so I don't know how useful they will be for sure.)  so they may be worth a look.  Maybe you will find something there that will save you some work!
Links:
http://www.finalfantasyd20.com/ffd20/index.html
http://ffsaga.wikidot.com/

GateKeeper_A, thank you for your insight. I see others have come up with the idea before me, but it's not quite what I'm looking for. It's at least something to reference to while I do my research on the subject, but it'll be a long time before I get it developed. I am participating in a Pathfinder's Campaign group myself, and I hope I'll be able to learn enough from playing the game to use in the creation of this FFd20 setting I'm brainstorming.

Regarding the Job system, I'm not really sure how to incorporate that at all. The way I see it, that would require you to carry a lot more sheets attached to your character, especially for magic classes. Perhaps a more open-ended job system would work, like what we've seen in FF12 and even Skyrim. This way, character development could be more skill and feat focused, stats generalized to however we'd like, and some added versatility when needed, perhaps. Maybe for simplicity, we can use the FFV job system as a bases for how growth works for job experience, learning feats or skills after using a job enough times. However, it's all still a hypothesis, so input would be nice.

Glad I could be of some small help! 

The Job System.  This has evolved a lot over the course of the series, so its difficult to know what EXACTLY you are looking for in building a playable Job System for an RPG.  But if you really think about it, there is already something of a jobs system built into Pathfinder/D&D in the form of Classes/Prestige Classes, and even Feats to a lesser degree.  While each Class is available from the start, you earn the ability to pursue Prestige Classes, or even the ability to take some Feats as you level up your character based on your BAB, Ability Scores, or even the assignment of Skill Points.

The first thing you need to do is decide what you want to accomplish with the Jobs System.  Can it be done with the Classes as-is?  Or does it require something more?  If it requires something more, then what kind of changes will you need to make?  Can it be done by rewarding characters with extra skill points or Feats?  Or will it require a major overhaul to the system?

I've been thinking about the Job System thing since stumbling across your thread yesterday, and so far, I haven't come up with much that is useful to help.  I even had a pencil & paper out earlier taking notes, but no luck in the results department.  One thing that I realized right from the start is that you don't want to carry around more than one character sheet, so whatever changes you make to the core rules would need to be something that you could do with either the existing character sheet, or a slightly modified character sheet.

The only thing I've stumbled across that may be useful is the system they use with the new Warhammer Fantasy RPG by Fantasy Flight Games.  (I haven't played it since it was in the Beta stage, so you will have to forgive me if my memory isn't perfect)  But with that system, I seem to remember there being a core character sheet, with a secondary sheet that listed the bonuses that the particular job you were using gave you.  It may be worth toying around with something like that?  Maybe with an index card (Or something about that size) containing the extra information for the job, so players can trade those out to show the extra information instead of going to the trouble of creating a separate character sheet for each job?  (Its not a great idea, but its the best I've come up with so far.  Maybe you'll be able to make something of it?)

Other than that, I cant really think of much that would help with the Jobs System.  But I'll be sure to share anything else that crosses my mind.    Maybe some stray thought or trivial idea will give you an idea for something that works perfectly for you?

Good luck!