I have an idea, it is a little less romantic but it is cool I think.
Ok so I am going to lay out some of the framework and we can work it together or whatever you like.
A private military company of special operatives who are also werewolves, the werewolf blood was given to them many hundreds of years ago. They find their selves in a war between a house of vampires, ruthless assassins with equal technology, it can be set in the near future but I had the idea of them kinda just being around our time here in the good year of 2015 ye-haw. BUT then again it is open for debate.
The vampire assassins could use swords, daggers, blades, claws, anything of that nature. Silenced weapons and all that spy stuff think... Splinter Cell.
And perhaps the werewolves could be more military style, like an actual company, Heavy military armor, assault rifles, things of that nature. I think it could be interesting.