"Rutile" is a codename I've chosen for this vision of what Drow (dark elves) in DF could be like. If anyone else proposes a different vision, I encourage them to adopt a different material-in-DF as a codename to avoid confusion.
(Some of the things in this thread I've suggested before in other threads.)
Before dealing with the drow themselves, one change to existing DF semantics is needed: underground wood (tower caps, etc.) would not be considered truly trees by elves or drow. So they would no longer count against elven quotas.
As I see it, Drow would be an offshoot of the elves who have been magically banished from the surface for acting too dwarfy. (Dwarfy meaning the way DF players behave,
not any resemblence to the ethics Toady officially assigned the dwarves...)
All drow have incurable cave adaptation, and their retreats are within the underground caverns. Both elves and drow have influence over the nearby furries, which explains why underground animalmen are nastier.
Both have an intrinsic "lust" for trees, but express it differently. Live trees are most preferable, but simply not available for the drow. So elves seek to keep trees alive, but drow try to surround themselves with dead wood bought from outside, as that is better than nothing. So instead of imposing a maximum logging quota, drow will try to negotiate a minimum log delivery quota.
If trees were women, elves would be like a hero who sleeps around but will always respect a No, and will be motivated to kill a rapist even if he doesn't particularly like the victim. Drow instead, are like ugly sex-starved otaku who actually consider FATAL a worthwhile game.
And speaking of FATAL, drow would have a "have its cadaver" spell of sorts. If they can get surface wood logs from trade, they will use them to create undead trees for their parks. Undead trees don't require light, although naturally occurring undead trees happen to be in lighted positions since they haven't moved since becoming undead.
While drow forging ability is inferior to that of the dwarves, they do have one edge - they can smelt some 20th-century metals. In particular, they will have access to titanium. Titanium can be considered a "living metal", almost as good as wood, since:
- it is very compatible with living things. Bone heals strongly around implanted titanium objects; in real life it is the only good material for the roots of dental implants.
- when alloyed with nickel, it displays a weird "shape memory" effect, which could poetically be regarded as lifelike.
- it cannot be reforged normally for the same reason wood can't -- it will catch fire before melting.
(As a metal, titanium is roughly as good as iron, but lighter. Perhaps a good choice for armor if you can't spare the adamantine, yet have dwarves who can't move full speed in steel.)
If you have no relationship with the elves, and have a path from depot to an underground map edge, drow caravans may arrive instead. Drow have wagons, making it worthwhile for a drow-courting player to make three-wide tunnel from his depot to the caverns. Drow caravans will not cross outdoor tiles.
Drow will pay above standard price for surface-wood products, and for ores such as rutile and bauxite that can be used for drow-exclusive smelting. They will sell aluminum below standard price.
Like surface elves, Drow will sell pets, but these will be of cavern species.
Drow do not participate in the regular city-on-city wars during worldgen, not for lack of inclination. They can't come to the surface, and the other races do not enter the caverns.
(I'll put this on Eternal Suggestions, although my vote goes to more practical things at the moment...)