Written? Sort of. It's in peices. Could I make it publishable quality if I had the time? Sure. Do you see how much junk is out there being published that isn't of publishable quality? Could/would other DM's use it? Probably. Some DMs seem to be using snippets of things I've put on EnWorld.
But is it publishable? No. I never made a concerted effort to be original. I was trying to support a game, not publish my own work. I liberally stole and borrowed from other sources. In fact, the original heart of the campaign world is evolved from the map of the known world that came in 'The Isle of Dread' back when I was a 12 year old just starting out DM. I moved somethings around the map to get the climates to make more sense, and much of the culture is just my fanciful interpretation of the few clues found there. New places appeared around the edges - the Matriarchy of Panonia, Highsheen, Murlgamor, the Trifani city states, the City of Dee, the Lochlands, the Keltan Confedarcy, and dozens of places with names even I forget because I've never ran a campaign there won't be found on anyone else's.
Plus, even my original ideas have been independently had by other people, so that things that at one time were 'far out' are now strongly reminesent of things that have already been published.
If I was serious about publishing, I could probably rework alot of it. I'd definately want to map a 'dream world' that existed parallel to world, and probably an underworld and overworld as well. I've never really done that, but as my homebrew matured, it got more and more tightly woven with arcane planes and I've always felt that these should be as detailed as the main world to really play the world the way I'd want to play it now. Plus, I've always loosely ran 'the thousand gods' of the world's pantheon, and just made up gods on the spot for whatever role that I wanted, but I've got alot of ideas in later years for structuring the panetheon and I'd want to at least give a paragraph on a hundred or two of the major deities, plus write up a chapter on the 'theology' of the game world.
All of that though comes rather secondary to having a family and a job right now.