For World Adventure Writing Month I plan to create a D&D 4th Ed adventure for the Epic Levels of 21 to 24. It's a some what daunting task I admit but it should be fun. I plan to break it up into 3 parts:
Part 1, Ascensions' Door: has the party pursuing a BBEG to the Elemental Dome. I estimate 12 encounters using Wizards' two page encounter format (24 pages) . There will be another 4 pages of background, 3 new magic items (1 page), 8 new monsters (mostly in the elemental theme, I guess 3 to 5 pages for this), 2 full page maps (over land and temple layout).
Part 2, Temple of Ascension: is set on a series of islands deep in the astral sea, I figure 18 encounters with a final battle against the BBEG, hopefully just prior to their ascension to god status. If they succeed, there are all of the materials and info for becoming a god them selves (which would then lead into part 3). In the case of Failure, BBEG ascends to god hood and the players are tasked with ridding the universe of the BBEG.
Part 3, To Kill a God/Setting up house: - is a hypothetical successor to part 2, as the players attempt to destroy the newly formed god (from part 2) OR set up shop in a newly created realm as gods them selves, or something.
Of course, given the amount that I have written so far (you are pretty much looking at it). My plans may change, fall apart or decompose into so much compost.