For the adventure proposal, how about something that's not been done since 1981's Isle of Dread: a pure exploration adventure!
Discover a new land and get to name it!
Interact with the natives, like monkey goblins or volcano-sledding orcs!
Discover new flora and fauna!
Get trade rights!
Map the area!
Claim it for the Queen!
Yes, we've returned to "The Isle" in the context of an adventure path, but it would be unique and its the quintessential plug and play concept.
And, after all, Paizo's promoting a whole pathfinder thing... what could fit better.
(And, in our litigious time, I'm more than willing to let you or anyone else nab this idea for a module without any compensation or recognition... I just want to plug it in and play it!)
I've always been partial to open-ended exploration of this sort and I tend to throw in one of these in most campaigns I run. Sadly I usually end up making my own since like you said, there are not many of these sort of adventures around.
That said it probably won't happen in the final 4 because it would be a hard sell. Thin plot, very open ended, and no concrete conclusion to wrap it up really. I think the contestants will be trying very hard to be clever and unique to pick up votes, and open ended exploration sometimes gives that 'is that all' factor that some folks don't care for. I would certainly give it a good look though :P
While I think the idea is sound, were you aware of Erik Mona's work on the excellent Return to the Isle of Dread in Dungeon? That's one of my favorite issues.
I think he's confusing it with the Savage Tide adventure path, which takes place mostly on the Isle of Dread.
What Samuel said, while adventure like that is definitely interesting (and that type of gaming often plays a big role in my campaigns), I'm afraid it's quite hard to write a great pitch for that in a competition like this.