http://www.nexusmods.com/skyrim/mods/32799/?

2014 Update... I've added four new versions. I corrected mild issues with a tiny out of the way building having gaps in it. I also changed the followers AI settings from no crime to any crime, so you can now use dialogue to tell them to steal or murder for you. Lastly in the 2014 update, some of the items that the merchants sell has had it's in game description made less glitchy.
Also did a little bit of rebalancing.

I've fixed some old bugs in my mod I released some time ago, in addition to new content. Including the ability to get cured of vampirism, rival vampire assassins who only follow the player when it's dark out, and try to kill the player both in Xemorah Island as well as Skyrim, paladins who hunt vampire players down (and who can become player companions if said player drinks the purgeblood potion to be cured of vampirism), some general rebalancing, and a severe weakness to fire and silver weapons for formerly overpowered NPC vampires. I also released a few more Youtube videos showing how to find the merchants/companions/bounty notes /etc/ in this mod, as there were complaints of them being too hard to find.

The possibly TLDR stuff is all below.

New Massive Updates:

Fixed lighting in a few cells to get rid of stripping, lowered a few objects in exteriors that were a little too high

All vampire drain health reduced to 17 per hand casting, Aundae to 20, this being the drain health spell my mod adds, not one added in vanilla or any other mods. Reason being that drain health seemed to be overpowered in previous versions.

The Blood Chamber has been slightly edited, in order to make it more friendly to characters who heavily rely on stealth. There is now a door where you teleport so you have more time, and ease starting off a stealth attack, and Zabhena Akar (who you probably have to defeat to drink the potions unless you're super sneaky) actually moves around, and doesn't constantly face where the player teleports 24/7 now.

The cell the Aundae boss is in, has had the flamethrower traps altered to both work properly, and do much higher damage.

Other than the follower NPCs none of the NPCs have dialogue, programming advanced dialogue is beyond my modding abilities, and this mod doesn't add in actual quests, just some in game journals with directions to NPCs the vampire leaders want you to assassinate. Also in response to complaints about the NPC vampires being overpowered, going into an enemy vampire base is intended to be a nearly a suicide mission, it's meant to be a nearly impossible challenge- although I have made the non-elite vampires much more fragile enemies if you use silver weapons or fire, which is both lore friendly, and solves a frustrating part of this mod for a lot of people.

Added content: Non elite vampires now take 6 times damage from silver weapons, and about 90% more damage from fire spells, this was done because they were nearly impossible even for high level players to deal with, and so they wouldn't win against nearly any NPC they come across in Skyrim. They will likely be able to still kill you in a few hits, but at least they are glass cannons now rather than "steel" cannons.

The Berne vampires have had their double casted paralysis spell reduced to last only one second, and the npc Berne vampires had their absorb health/magicka abilities reduced to absorb only 5 health and 15 magicka per swing, they used to absorb something ridiculous like 79 magicka and 80 stamina per swing or something in that ballpark, so they still absorb magicka and stamina quickly, but not like they used to. The Berne Shadow Spider was changed to the Berne faction as it was in the wrong faction, and I fixed a glitch so it can actually do damage now, it does very little damage no more than an average dwemer spider, but is very resistant to spells.

Elite vampires take more damage from fire though not as much as non elite vampires, and double damage from silver weapons, you will only encounter elite vampires inside of their bases though, so you don't have to worry about being unable to explore without encountering an elite vampire out of nowhere. The boss vampires have actually been buffed so they take half damage from everything, and now they're even harder to kill.

I've also dramatically improved the scripting for this mod, now doing more things with less scripts, this means less script bloating, and best of all, you now only need to drink one blood potion to transform into a Morrowind specific vampire. The "all vampires" potion has been removed entirely, as the passive buffs it applies to players of all three factions, has simply been added to the other potions. I've also removed the locks that go to the player follower homes, and player homes in this mod, as I've figured out how to use scripts to enable/disable NPCs.

I used to have it where you had to grab a key to be able to access the area where the faction specific companions were, but now these companions only spawn if you drink said blood potion, so there is more explorability, and immersion than there used to be in this regard. You can now explore all of the vampire bases fully, with no restrictions- other than being attacked on sight by enemies of course. I also fixed a teleportal by the well under Teldirran, so now that when the player uses the secret door to get in there, they won't get stuck anymore.

Helnarr-Jo Sirahir now has a levitating animation which fits him being a super powerful mage who levitates a bunch of objects with magical powers, and his thrall who lays down on this ruins alter, now lays down completely still on his back in a much more corpse like manner, rather than on his side like a sleeping person, which feels much more immersive and appropriate for a thrall who is only alive physically. Perhaps most importantly, I've created several NPCs who will only be enabled based on what potion you drink.

If you drink the Quarra potion for example, Aundae and Berne enforcers and assassins will now stalk and try to kill you. Regardless of which vampire faction you join, there will also be a group of paladins wielding silver weapons and fire spells who will also hunt and try to kill you. The group of player hunting NPCs will differ a little bit, depending on rather you're on Skyrim, or Xemorah Island. You will encounter more stalkers on Xemorah Island but also some in Skyrim.

Lastly, since it was requested by a friend of mine, I added in the option for a potion to cure the player of vampirism. It removes vampirism, and even removes all of the unique vampire specific abilities that my mod adds. When you drink the potion your former vampire faction, will turn hostile towards you, and the paladins who used to hunt you down, will stop following you, and stop attacking you.

You will also afterward gain the ability to have a paladin companion. Out of four optional paladins. Three of them using two handed weapons, and having perks to support that, and one paladin going sword and board. With perks to support that. The paladins all have a fire based spell that does slightly less damage than firebolt, but lights up the room, and turns undead, and they all have the healing spell closewounds. Since they are LAW abiding PALADINS their AI settings have been set to no crime in contrast to the vampires.

Since one of the paladins is a female khajiit Paladin Sajilvadni, whom vanilla Skyrim doesn't have follower voice dialogue support for, you will need to use the mod MFVM - More Follower Voices Mod Plus Khajiit Marriage in order to recruit her as a companion, although if you just can't use that mod for whatever reason, there are three other 2 hand perked paladins you can choose from.

Lastly I already know ahead of time, that some players will not like being endlessly hunted by rival vampires every time they respawn, so for those players I created a place called Palmordoth, and you can activate a chain which will "shower" you in this special water that permanently masks your blood scent from those vampires in question. Afterwards the AI packages which make said vampires follow you will be disabled.

In order to ender Palmordoth you need to journey deeply into all three of the vampire bases, and get the three keys to the three doors in question. And yes, drinking the purgeblood potion, will disable the vampiric (or vampire affiliated in the case of Helnarr-Jo's thrall) companions, and replace them with hostile versions of themselves that attack the player on sight... Because of course, they feel betrayed by you for rejecting their bloodline, and will forever hate you if you do that.

Depending on which potion you drink, a specific spelltome will spawn, the summon Quarra Great Hound tome will only spawn if you drink the Quarra potion, and the summon Berne Shadow Spider tome will only spawn if you drink the Berne blood potion, and the Aundae summon phantom spider tomes will only spawn if you drink the Aundae blood potion. You will retain the ability to do these summons even upon being cured, view them as basically being like quest rewards for those who want to become ex vampires, although you'll lose every vampire specific ability you had.