There is an order referred to in a book written by a vampire of Cyrodiil. It's nothing you can technically formally join, but it kind of claims all vampires that live within society as a member. It encourages vampires to excel in the political arenas and things of the sort. Infiltrate and control from behind the scenes. Really, they remind me so much of World of Darkness' Camarilla that it's a little bit bonkers.
Cyrodiilic Vampires are just plain awesome. Too bad we never got to join them.
You wouldn't happen to know the name of the book would you? It sounds interesting, and i want to see if i can find it.
This book: http://www.uesp.net/wiki/Lore:Manifesto_Cyrodiil_Vampyrum
More or less the Camarilla and the Venture from World of Darkness, or the Illuminati or even the "Sith" from Star Wars.