Ther is also a scamp in an orc house in caldera with 5000 gold to barter with.
if you wait 24 hours his money goes back up to 5000.

There is a creature called the Mudcrab Merchant. He is a mudcrab. I kid you not. He resides on a small island between Vivec and Tel Branora. Sort of south of Suran. Anyway, the island is beside a Daedric ruin and the mudcrab has 10,000 gold with which to barter. He buys weapons, armor, potions, scrolls, bowls, plates, silverware, and anything enchanted, but he does not buy alchemy equipment, clothing, lamps, cloth, ingredients, or books. If I missed anything, I'm sure you can find out yourself when you see the little guy.
Oh, and don't give up looking, he's there, he's just a mudcrab, so he's hard to see.

also there is a armorer in the great bazzar that has 10,000 gold. I know yes its not as cool as a bartering mudcrab, however it is easier to find.