Elves as "closer to nature and lower-tech" - give them a revulsion to metal?

[The Colonel]

Continue the "growing" theme - the elves work stone by using some form of magic to make the stone grow into the shapes they require - all of their buildings are effectively one-piece castings extruded from the bedrock, possibly with the occasional welded on bit. This would have the added bonus of giving any elven buildings the opportunity to have a delicate, organic look with traceries and flows and such things. Stone tools could also, presumably, be grown into shape.
Singing would seem a thematic way of doing it.