Took a quick look, couldn't find anything of the sort. Great idea though!
I think there should be assassins for the Great Khans, Fiends, Chairmen, Omertas, White Gloves, Crimson Caravan, Van Graffs, Gun Runners, Freeside ((hired) thugs), The Strip(A lone Securitron), Kings, Powder Gangers and Westside Militia too.
Most wouldn't be very strong or numerous however. Most would be simply hired thugs/mercenaries.