Yeah let's not forget DAOC's Darkness Falls, still waiting for a game to recreate that kind of contested dungeon properly. Am only level 30 here though so maybe there's something similar?
Also I think it's possible to have challenging pve raids/dungeons without having to go down the whole tiering detatched-from-rest-of-game path. You just need to make sure the rewards aren't independent from the rest of the game, but rather are part of a larger whole. So a successful guild needs some raiders to beat content for material x, which when combined with crafted material y and pvp raided material z leads to something useful for the guild. It's only a problem when the raiding is the only way to get gear, and/or that gear is only good for further raiding.