Okay. Let's do it.
Perhaps we can even collect the ENWorld Braintrust to help design it? Put up some polls to determine plot points and adversaries, and maybe whip up a Kickstarter to get it all funded?
I'm probably way too optimistic....
Haha, I think the ENWorld overlords are a bit tied up with a little project called Zeitgeist at the moment.

Kickstarter is a very cool concept; a friend just had great success using it for a line of baby sleep products (no not whisky).
Wait...you're a quarter serious, aren't you?
I think this is a great idea, despite not knowing much about its market potential.
Yeah I just write and get published a little, the business costs and reasonable ROI for publishing game material is beyond me. Though if something like this happened it would probably be a limited run thing appealing to a small group of gamers.
If we do decide to do this partially through Enworld, I would be very interested in contributing; perhaps through designing an encounter or two (all creature stats, I would assume, would have to be custom created).
I think that's jumping the gun a little bit. So I'll jump a little with you
<4e speak>I was playing around with minion varieties and I think there's lots of cool design space there. Recently I came up with the Forgotten Kings, basically a ghost possessed statue (level 11), that were only killed by one of these conditions: a single attack dealing 50+ damage, a critical hit, hitting them in the right order (4 appear in the encounter), an attack by an heir to the throne, by a Lawful Good character, or with a Kingsbane Weapon.
Tie it in a with an existing literary or cinematic product and one has a ready enough audience.
I've been really impressed with Green Ronin's approach to literary setting projects like Black Company and Thieves World. Also Goodman Games' Death Dealer for 4e was based off a comic book by Franzetta.
Campaigns-in-a-box have been produced for 30 years, starting with Judges Guild "City State of the Invincible Overlord", followed by TSR's Greyhawk. This proposal sounds like it wants a lux presentation, which is cool, but it is not anything special.
Of course you're right - the idea is not new - but most of the products that have been mentioned are more aptly described as City Supplement or Mega-Dungeon. And those can make great campaigns but that's by what I had in mind exactly...
The old City State products were city guides and maybe campaign outlines, but not complete campaigns by any means. Maybe you're referring to the 2004 Necromancer version of City State? That one was bigger so maybe it was more than a big city supplement?
Sacrilege! real women fight with spaulders and cuirasses!
http://images.fanpop.com/images/image_uploads/Joan-of-Arc-leelee-sobieski-321505_600_740.jpg
but I want to hear what the campaign is about.
I was about to answer your question with a gushing description of the adventure series I've been working on, then realized (a) I am no publisher and it's my pipedream, (b) you're probably asking rhetorically, (c) if I told you the concept could blow your brain with awesome, and (d) I don't want to dominate the thread with my particular story.
But in principal I agree with you, none of the bells and whistles matters until an adventure's story is solid.