Anyone know any mods that give you freelance Assassination mods? I mean not every assassin is so sick that they want to join the Dark Brotherhood? Can't an assassin work for the Imperial council if they want, killing off people who are inconvenient to the government? Or be hired by guilds for one time hit jobs? Anything along those lines exist so far and if not, will anyone think to make a mod like that?

Well, there is http://planetelderscrolls.gamespy.com/View.php?view=OblivionMods.Detail&id=4514. I'd guess that most actual guilds would not allow such a crime to be done as part of their work.
Besides, the Dark Brotherhood holds the niche well, and unless I'm horribly mistaken, tons of people hire them to kill people, be it for being a all around jerk to everyone, or just getting between them and something.

ah thats a good start, definitely the kind of thing I had in mind.Still I would love to be hired by people directly rather then accept it from a note left there. Of course AC2 uses carrier pidgeons to give you contracts and such but yo need to finish a quest before you get the option.

In http://tesnexus.com/downloads/file.php?id=8714 you get an offer you may like.