To date, not a lot of true megadungeons -- as opposed to just really big dungeons -- have been published. I'm starting to wonder if the reason for that is that it's difficult to present a megadungeon in a format that's both comprehensive enough to do justice to such a campaign tent pole and yet easy to use in play. Then there's the additional factor of how much detail a megadungeon product needs to be usable and whether too much detail undercuts the very essence of a megadungeon.
So, today's question is this: assuming you're interested in megadungeons -- if you're not, please don't use the comments section to express your disinterest -- what would be your preferred format? Feel free and assume that there are no limits and go with what you would consider to be the ideal format for presenting a true old school megadungeon.
I'll admit I'm very curious to hear what people have to say, since it's a topic I've thought about myself at some length and that I'll share in an upcoming post.