Depending on how often vamps need to feed, I may specifically arrange for a vampire to defend my fort from invaders as a part of my military in exchange for stable living accomodations and the occasional midnight snack.
Here's how I'm thinking of setting it up:
[Private Vampire Luxury Suite] -+- [Feeding Chamber 1] -+- [Feeding Chamber 2] -+- [Main Fortress]
- The Luxury Suite contains a barracks designated from a piece of furniture for the vamp to train as well as a backdoor leading to the rest of the fortress. Keep this locked for now.
- The Feeding Chambers are kept constantly stocked with 1 migrant each, along with enough supplies to keep them safe and happy for at least two months.
- Burrows are used to herd the vampire (who has been drafted and equipped beforehand) and its lunches into the rooms.
- Once in the Luxury Suite, the vampire is assigned to train; as it only needs to drink (as it were), not eat or sleep, it should gain skill relatively quickly.
- The doors between Feeding Chamber 2 and the main fortress are to be kept locked to prevent the cattle from escaping.
- Similarly, the doors between Feeding Chambers 1 and 2 are to be kept locked, to prevent the cattle both from snitching after witnessing a feeding and from making friends with each other.
- The doors between Feeding Chamber 1 and the Luxury Suite are to be left unlocked, so that the vamp can freely access its victim as needed.
- When the vamp has drained the subject in Feeding Chamber 1, unlock the doors between Feeding Chambers 1 and 2 and burrow the other cattle into Chamber 1. Afterwards, lock the door between Feeding Chambers 1 and 2, open the door to the main fortress, and burrow a new subject in. Afterwards, lock the door. Your vamp's larders are now restocked.
- To deploy the vampire, restrict the cattle to Feeding Chamber 1 and the vampire to the Luxury Suite, then lock the door between them. Afterwards, unlock the backdoor between the Suite and the rest of the fortress and station the vampire wherever there is killing to be done. After it's finished, station the vamp back inside the luxury suite, lock the backdoor, and re-open the door between the Luxury Suite and Feeding Chamber 1.
Assuming this plan works, it should prevent vampires from feeding on important dwarves while simultaneously giving wax workers a purpose in life.
It may be preferable to seal off the hospital/bedrooms while the vamp is out, to prevent accidents.
Also, increasing the number of Feeding Chambers could be helpful in case the fortress doesn't get any migrants for a long time, as the dwarves won't make any new friends while they're in there.
Threetoe said that his vamp survived fifty consecutive hammerstrikes, so the lack of armor experience from drills shouldn't affect the vampire's combat effectiveness (assuming Toady didn't change anything).