the final dungeon sounds great.
i had a similar idea, but mine would be for 2 pages.
1 page - a 10 room map,
the other page - a bare bones description. (1 or 2 paragraph background, 1 or 2 npcs, + the rest just a list of room contents).
this would be the "level" of the month.
it could be a 10 level dungeon or a dungeon with infinite levels.
it would be ideal if DMs could pick any of the levels they liked to create a unique dungeon (the only problem is they'd have to make sure its balanced with their PCs).