The Elven Maiden

This is a quest you will get after you have sold 100 gold worth of stolen goods to Ongar. Once you're able, go back to Armand Christophe and inquire about another special job.

He'll tell you that the guild has received a request to obtain a bust of the late countess of Cheydinhal.

Find a beggar in Cheydinhal and get their disposition at 70 or over. Then ask about it--expect to pay them for the information, of course.

The beggar will tell you that the Count commissioned the bust and that it's near her tomb in the chapel undercroft. There's also a guard posted, and there's something about the area possibly being haunted.

So go into the chapel, and head down the stairs and turn right once you reach the bottom. Pick the lock of that and immediately go into sneak mode once you are on the other side. It would also be a good idea to save.

Keep to your immediate left--to the opening on the left--and sneak past the guard. A ghost will appear, but I don't believe it will attack you. I walked past it and didn't suffer any HP loss, so I believe it's a safe assumption.

Anyway, fast-travel back to the Imperial City Waterfront.

When you start to head towards the meeting place, you'll notice a bunch of guards running around and you'll get a quest notification that the area's crawling with guards looking for Armand, and that he isn't going to show. It'll prompt you to go find another member of the Thieves Guild, so go find Methredhel in her house.

She'll tell you that there was no person who commissioned the guild to get the bust; it was set up to out an informant. It's someone named Myvryna Arano. Your job is to plant the bust in Myvryna's house and tell Lex that SHE did it.

So leave Methredhel's house.

Turn to your right and go into the house right next to Methredhel's. You'll have to be very careful picking the lock because of all the guards. The cupboard is on the right side of the room, near her bed. All you have to do is press the spacebar when you're near enough to the cupboard and the quest notification will pop up that the Bust is now in the cupboard and you can go tell Lex now.

He'll be walking around the waterfront, so just find him via the green quest marker that will appear on your minor map.

Get his disposition to at least 75 and then tell him.

Follow him to Myvryna's house and watch the ensuing little "argument." After it's done, you'll get a quest notification to wait until the NEXT midnight to turn in the bust.

So go to the "garden" and then wait until the next midnight. Turn the quest in.

Your reward is 100 gold, +2 to your infamy, a promotion, and access to another guild fence, Dar Jee of Leyawiin. You also don't report to Armand anymore. If you question him about special jobs, he will direct you to S'krivva in Bravil.