Did a search, didn't find anything. If this is a repost, get it deleted, I hate clutter.
SO, I was running around IF on my lvl 80 pally, waiting for my hearthstone to cooldown, and decided to actually go up the stairs in the hall of mysteries. (The room you appear in after taking a portal to IF, from Shatt, Dalaran, Mage, whaterver). Saw an NPC with a blue question mark over her hear, went to talk to her, and she gave me a book. This book was one of those items that started a quest, and that you had to be level 29 or something to use it. I just thought to myself, what the hell, I'll give it a shot. Started it, did the first one or two quests in the chain, and had to go run a friend through ramps. Came back to it a few days later, and noticed that it was yellow in my book, and was awarding 16g. Started to finish it, and each quest in the chain gives either 6g or 16g at level 80, up to a point where an NPC gives you a shopping list, and then it turned grey for me.
In any case, I doubt that the devs intended this, as the quests are a breeze (killing defias in westfall?), so if you are bored, and want some extra g (and havnt already done the quests), then here you go.
Sorry for the wall o' text. >.<