Hmm...I think I might have a few ideas for rules for the vampires.

A vampire may not kill another without first taking it up with the regional council. If teh vampire is deemed to have comitted a wrong they may be executed according to teh wishes of the accusor. The punishment may vary depending on the severity of teh crime.
(for example if an idea I had (based on the vampire series I just read) is that when a vampire does not get the blood it needs it shuts down and goes into a sort of stasis state but is still aware of it's surroundings but can't move. According to vampire law this can be used as a punishment for law breakers if their crime isn't severe enough to warrent a death sentence but is notisable enough to cause some action to be taken (for example endangering the safety of the vampires as a whole or abusing their authority over a younger/weaker vampire)

And thank you. I definitely thought so. The minute I saw him it clicked.