But, I also created an alternate save, where I tested out my ability to kill a bunch of vampires (not that they are any stronger or better than the typical raiders in the game, heh). Turns out Vance's trench coat is not only very cool looking, but has some kickass bonuses to abilities - something to the effect of INT +1, CHA +1, Small Arms +10...
Needless to say, I want the thing on my main game now, if only because it's called 'Vance's trench coat' - oh, and because I've specialized in small arms weaponry, too.
I think I might just put aside the moral high ground and take it from his rotting corpse, despite trying to run through the game as a 'good' guy.