As a fan of The Lord of the Rings trilogy, this would be a great idea. I always wanted to have a Sim that is Elvish, but I also love would be the clothes that they wear. Each Elven house are different each other as well as each can marry their own kind. But sometimes, they can marry a mortal like Aragorn and Arwen.
For example:
Ñoldor aka Deep Elves: Most notable: Lady Galadriel, Lord Celeborn and they can be found in Lothlorien. Hair color: Usually black, occasionally golden and red, rarely silver
Sindar Elves aka Gray Elves: Legolas, Thranduil and they live in Mirkwood. Hair Color: Usually black, occasionally silver
Half-Elves: (they were given a choice to be Elven and immortal, or to be counted as the race of Men and receive their gift, mortality and death.) Most notable: Lord Elrond, Lady Arwen. They are found in Rivendell and Arwen can also be found in Lothlorien visiting her grandparents Lady Galadriel and Lord Celeborn.
For those who don't know what a Dark Elves are and from Lord of the Rings lore: they are were the Elves of Darkness: those who did not embark on the journey over the sea to Aman and behold the light of the Two Trees of Valinor. Most notable Dark Elves: Eöl, known as the Dark Elf, was the great smith and his son Maeglin.