No, everything
has not been done. I'd like to see something along the lines of The Mountain Witch, but for d20/OGl. I'd like to see an entirely self-contained, multiple-player, pick-up game under one cover. Specifically. . .
I want a short campaign (something like
Red Hand of Doom or
Expedition to Castle Ravenloft), a selection of pre-generated characters (preferably more than the number required to play the campaign), and a short, complete, set of rules (e.g., Core Elements, Seige Engine, Wordsmith, D&D Minis rules, etc).
And I want it all under one (preferably hard) cover. I think that selling such a product for around $25-35 dollars is do-able (depending on the length of the book and paper quality). Naturally, it would also contain text boxes with advice for customizing encounters to enhance replay value (and, possibly,
multiple end-game scenarios).
The Terrasque itself couldn't keep me away from such a product line
