So for a well I've been thinking of doing a character that raises the dead. Im not sure yet. But, I also have been thinking of doing a true nightingale and roleplaying as a loyal one.

Any lore on if raising the dead would be frowned upon?

Not as far as I know. Generally the thieves guild has frowned on killing people, but only in a Dark Brotherhood style, they don't have problems with adventurers killing bandits or whatever. Nocturnal IS the patron of darkness, so she probably wouldn't mind vampires, and they tend to be necromancers, so, I cant see anything wrong with it. Good Luck!

The entire Mages Guild in Oblivion constantly reminded the player how it was their goal to root out Necromancy. It is even noted by the College that it should be practiced inside the College walls.

Even the towns people will comment on you having a Dead Thrall. Some will not even open dialog with you if you have one active.