The Moon Game elevator pitch

Take your generic fantasy good guys, make them a bit shinier, and put them in a world without orcs or goblins.  Then drop Dragonmech's moon invasion on it, but without the walker twist, and probably with less of the constant lunar rain.  Advance the setting a bit, and set your players loose.  I'm looking at pulling some ideas from early D&D as filtered through the OSR, especially the idea of a "tent-pole" megadungeon, heavy use of random tables to generate setting, and lots of player freedom in terms of goals and approach.  However, this is going to have more of a built-in metaplot than is common - the monsters are coming for everyone eventually, if they aren't stopped.

Antagonists:

• Duergar, dwarves cast out of the world by the Earthfather before the dawn of man
• Lunar Dragons, pulled whole cloth from Dragonmech
• Apes of some sort, undoubtedly carnivorous
• Golems, the Duergar's "original sin"
• some more bizarre lunar ecology 
• giant bugs
• carnivorous, poisonous, or otherwise inimical plants
• domestic animals

Groundlings:

• Plains Humans: feudal, knights, tournaments.  Think Gondor, MTG's Bant, and a bit of aesthetic influence from 40k's Black Templar, Grey Knights, and Dark Angels.
• Barbarian Humans: Savage and fierce, but not horde-forming or anything.  aesthetically, dungeonpunk Cimmerians and MTG's odyssey and mirrodin block barbarians
• Elves: Mostly the LotR movie take - they have cities in the forest, not villages.  probably not going to use tolkien's fading angle.
• Dwarves: craftsmen, warriors, dwell in underground cities, moria-ish I guess? primarily a Norse angle aesthetically, with roman-style armies.  probably some sort of ancestor-golems along 40k's dreadnought lines, but not purely warriors. (I think a giant dwarf-golem smith making things by just squishing the metal into shape is awesome, and you should too.

I'm not yet decided on a ruleset - I have an interest in trying out some of the old-school stuff (B/X sounds up my alley), but most of my gaming so far has been 3.X with some power-ups (Frank and K's Tome series).  I'm also thinking of doing an e6 game, probably with some mods to 3e's base classes and feats to make it more fitted to the level cutoff.