For a while now I've been working on my own version of the most famous dungeon in the world; Castle Greyhawk. I've got a bunch of levels mapped out, and some are partially keyed. I'm trying to make my version of the famous Castle ruins as compatible with the known lore as possible. That is, you should be able to take one of EGG's stories that have appeared in various venues over the years, read it, and be able to retrace the steps of the adventurers without contradiction. It won't be a perfect replica, obviously, but it will be as true as I can make it without having the original maps and key.
The project itself is on hold for the moment for a couple of reasons. First, I'm in the midst of my "Greyhawk Lore" project, in which I'm going through all of the public forums I can find where Gary Gygax, Rob Kuntz, etc. etc. etc. did Q&A with fans, and doing a copy-and-paste into a reference file of all the material that pertains directly to the Greyhawk campaign as it was, or in some cases, as the originals intended it to go. I'll be making those reference files public as well, but it's an enormous task!
Second, I'm waiting to see what Troll Lords Games comes out with this summer. The first of their Castle Zagyg books, detailing the Upper Works and first level of the dungeons themselves, will be coming out. This is Gary Gygax's vision for how he wanted the dungeon to be presented to the public, so I would like to see how it looks before I continue on with my own levels, just to maximize the "look and feel" intangibles.
At the moment I'm not too worried about running out of material for my own players, but I'd like to keep well ahead of them when it comes to exploring the ruins.