This one sounds potentially good if the execution is as good as the concept, but is this one even in print yet?
As is pretty (non-WOTC) common, the PDF is available. I confess that since I pretty much read most stuff on my iPad, although I do order the physical copy, it often sees little use. So ... yes, it's both available and not in print!
And the execution is really, really good. Frankly, I have very little interest in mega-dungeons and found the concept of living ones a little silly. So despite being a big fan of 13th Age, I didn't jump at this. In fact, the only reason I got it was that it was Sunday night, and I had a game to run Tuesday and was desperate for runnable ideas, and the writer, Gareth Ryder-Hanrahan has done kick-ass work on numerous other products and systems. So, having some free cash and being lazy I bought it and had a quick look for stuff to run.
Six hours later, at about 3am, I dragged myself off to bed and spent the next day trying not to completely convert my campaign to be just running this module. I think I've mostly succeeded, but it was close. What works best, to me, are the numerous hooks and adaptations. Not just the overall plot but most of the subplots have sets of variations for different ways to run and present things (and overall villains). There is an extensive set of non-dungeon adventures to tie into the dungeon, and even the dungeon is modular, with entire bits you can run / leave out / add to / re-purpose.
http://www.pelgranepress.com/?p=13408