I've played a campaign previously with ffd20 and had a blast doing so. It's basically a pathfinder homebrew and I had a lot of fun playing it, looking to scratch that itch as a player. I would consider running one myself but I'm not a great Pathfinder GM.

http://www.finalfantasyd20.com/

Another Final Fantasy homebrew I've played and run before is ffd6, which is a little more combat-heavy and abstract. Numbers represent the video games rather nicely in my opinion.

http://www.giantitp.com/forums...28Complete-System%29

Which Final Fantasy game are you looking to simulate. To my mind, there is a considerable difference in the worlds and a slight difference in tone from one game to another within the series.

I'm not looking for any specific setting from any of the games, just something that fits the high fantasy optimistic tones and involves chocobos, airships, buster swords etc.