Oblivion's Ayleid ruins were in fact tombs and sanctuaries, not residences. Look at White-Gold Tower and http://images.uesp.net//1/1c/Carac_Agaialor.jpg, they lived on the surface like nearly all other elven races. This makes sense, given their reverence toward the elements (particularly light) and their tendency toward nature symbolism, particularly trees and birds. Their ruins are not extensive on the surface, presumably, for the same reason that the ruins of conquered civilizations on Earth are typically not extensive-- centuries of looting, encroachment of the environment, and exposure to the elements. I don't think the Dwemer ruins were particularly well-done either-- bedframes were found right next to massive turbines, and they generally felt much more like dungeons than cities. :grad:

@OP-- I would suggest reading http://uesp.net/wiki/Oblivion:Glories_and_Laments for inspiration on Ayleid ruins. I don't think I ever encountered a ruin this cool in the game, and it might be a good starting point Plus, this way whatever you do is lore-friendly!



I would also suggest adding cultural artifacts (ancient weapons/armor, misc. items, etc.) and unique creatures. With regard to the latter, Ayleid specters, magical wisps, and flesh golems would probably not look out of place. And maybe the lich of an Ayleid king for a unique encounter?