An idea from when I was in DC: girl working for a government agency meets guy who might be a werewolf. Her boss is Anita Blake (a much older Anita Blake, who is now in DC trying to influence policy making about undead and supernatural beings). Something happens (well duh). I’ll have to search back for the idea in my email archives.
Anyway – the same world, but this time a wife either kills her husband or witnesses his grisly death and is a suspect and becomes a widow. Then the bad husband returns as a vampire. So – is she still a widow if her husband is undead? I expect there’s a lawyer/church group out there who wants to prove or disprove the lasting tie of marriage, and a detective who wants to prove that she killed her husband. And then there’s the vampire who did the killing. Did he or she want the bad husband to be a vampire or was the turning a mistake (and if so, how does that work?) Does the wife find lasting romance with her remade husband, or the vamipre, or the detective? Does she become a vampire herself? Are there two vampires – a bad murder and a responsible respectable one?