Basically you need to roll a magicka based DK with sword and shield, or go with the sorc builds (for example the ones above) as these are the only two classes with a reliable lock down for vampires (encase and dark talons). Sorc might opt in for switching one of the skills for bolt escape with morphs to match the mobility of vampires.
Or you have to go vamp yourself.
If you are focusing to fight vamps, go for dawnbreaker of smiting as an ult instead of atronach. You can also go for something like Power Overload for AoE heavy dmg. Atronach isn't really a good choice against vamps IMO.
All in all, things require testing, but on paper it MIGHT work. Just do not rely too much on silver bolts killing vampires, use it more like a harass tool with an odd bonus once in a while, and remember about holding some stamina for defensive purposes.
you might also think about switching the 5th skill for bolt escape on second tab. playing sorc without the super mobility they offer is limiting your options. (besides using ball of lightning and then following up with encase can give you enough of time to kill them)
build items around magicka pool and magicka regen.
Silver bolts with the leash morph is okish for harass, but has big drawbacks. It costs stamina, and quite a lot of it. It is very RNG based, and RNG is something you want to rely on least when in high level gaming. Leash pull won't work if your target will break the hard CC initial knockdown effect, and it also won't work if you are trying to pull the target back, when he is still knocked down or in the mist form. As a harass tool it is ok, but remember that if you will burn your stamina, you will be susceptible for lockdown (stuns, roots, snares, fear). Unless you are going with a team of people who can save your butt by focused healing and taking aggro from you when you are in trouble, then keep your stamina bar around half full
The banish works in PvP, but you should not rely on 5% chance, when your skill is not spammable to overcome the RNG (Random Number Generator). Silver bolts are not spammable (high cost and takes from stamina pool). Use them, but use them with care, as they will leave you defenseless if you will burn too much stamina.
Hi guys, i have read the comments so far and it seems like that the main focus on this discussion is based on skill/built based 1vs1 fighting a high level vampire. PvP in ESO is considerably more than this aspect only. Personally i do not expect single 1vs1 fighting but moreover small group encounters during a siege on any fortified position. Dropping oil comes to my mind. I often hear vampires complain about the initial damage and the damage over time effect to be a death sentence to them. Fire balista should work too. Any other strategic advantage should also be approved.
Veteran level in PvP is desireable as by then you will not be scaled up. I do not know if you have noticed it or not but level 40 onwards being scaled up may actually hinder you as long as you did not reach Veteran rank. I know that some of my guildmates have less armor in cyrodiil than outside(eg. 1800 armor but because of being scaled you have like 1300).
Oh and yes you might think that it is only a small difference but i can guarantee you it is a huge difference. You might have had a total different outcome when you and the vampire would both be at the same level.