First of all, I want to apologize in advance: English is not my first language, I'm Spanish, but I think I can at least write this build and make it understandable.

With that said, I've never played a tank Vladimir, not even before the huge nerf. I'll explain it: Vladimir's passive is Crimson Pact, before the nerf you gained 1 AP for every 25 hp, and now is 1 AP for every 40 hp.

I don't consider this to be a tank build, even though you'll be able to withstand a lot of punishment. More on that later.

Ok, red for magic penetration, since I need to maximize the little damage we're going to inflict. Yellow, I go for hp, for a strong early game. Blue, I go for CDR. This is an important point of the build: I'm going to spam sanguine pool as much as I can, and I want the blue buffs to be avaible for the mana spellcasters in my team (I play a lot with a Swain character: Swain + Blue Buff = Permaultimate). Ok now, I love the Greater Quintessences of Swiftness, they give a small but decisive boost of speed, allowing you to harass the hell out of any champion in mid, unless they have a Janna or three Greater Quintessences of Swiftness as you.

Standard masteries for Vladimir, enough Offense for Archaic Knowledge and nonmana Utility masteries.

Start

There are three ways to start a game with Vladimir and this build.

1 - Start with Ruby Crystal, so you have a nice amount of hp to start with. 700 hp or so should be enough.

2 - Start with Regrowth Pendant if you're going in mid against a heavy harassment champion, such as another Vladimir or any range dps.

3 - Start with Boots of Speed if you're up against a weak champion in mid. The speed you'll have should give you an easy time harassing and getting some easy kills around level 5.

Early

I find pretty easy to return to base frequently with Vladimir. Since farming with Vladimir is even easier than that, wait until you have 1600 gold or so and start harassing your enemy, forcing them to go back to base.

If they don't just kill them when you get to level 6 with a little tower dive. When they are half hp, do the combo, r -> E -> Q -> W -> Q, Ignite for ensuring the kill and Ghost so the tower doesn't kill you. If your enemy doesn't fall with this, he'll go back to base to heal. Go back and buy Ionian Boots and a tome.

Next time, return when you can buy the Hextech Revolver if you get your enemy out of the lane.

Mid / Late Game

Now we start building and filling Warmogs. For this you can keep farming in mid if your enemies leave you alone. If they start ganking play safer under your tower or start ganking yourself. When the teamfights or pushes start make sure you have at least one Warmog to fill its charges.

After the first Warmog it should be easy to buy the Will of the Ancients. This item will make the healing post-Sanguine Pool almost enough to heal the damage it inflicts on you.

A second Warmog, for more Health boost.

Rylai is a must for Vladimir, its bonuses are perfect for Crimson Pact and it makes your Transfusions slow enemies so you can eat them with Sanguine Pool. While you farm for Rylai you'll fill the second Warmog almost completely.

I've only ended the build once, and I didn't know what to buy. I thought, what the hell, another Warmog! This item may be changed for another: it's unlikely you'll fill the third Warmog.

I've not given it much thought because my games usually end at 25 minutes, but I guess you could change the third Warmog for a Sunfire Cape (if the other team has some nice dps), a Force of Nature (if the other team has powerful spellcasters) or a Guardian Angel (this item will give you a resistance and armor boost, and it will allow you to cast Sanguine Pool after you die).

If the other team is wise, they won't focus you right at the start of the teamfight. They can see your items, they know you're not a nuker. They are partly wrong.

While your team is receiving punishment you can blast the enemies with Tides of Blood, and making Transfusions to the squishes and carries.

Sanguine Pool

Sanguine Pool is your main weapon with this build. It does abusive damage when the enemies are together, but you must remember that this spell deals damage to you, 20% of your actual hp, so it's better to cast it when you've been damaged (at the end of a long game, if you have 7000 hp, if you cast Sanguine Pool at the beginning of the fight you'll inflict 1400 damage to yourself just pressing W, so be careful).

Sanguine Pool is a nice way to escape from a gank, and, combined with Ghost, a nice way to pursue a fleeing enemy.

I usually wait until the big ultimates have been used to cast Sanguine Pool. The cooldown of this spell, in level 18, should be around 9 seconds or less, make sure you cast it at least twice in each teamfight, to maximize the damage, even if the second time you do it to chase an enemy

As I stated before, this is not a tank build. You have no resistance whatsoever. You can tank some damage and avoid powerful skills with Sanguine Pool, but you're not a tank.

The reason I focus on hp in this build is because of Crimson Pact: With a lot of hp you'll be able to tank some damage while your ap is being boosted by your hp.

But, as awesome as it may sound (and believe me, it is), a lot of hp and no resistance leaves you helpless against some champions. You must keep an eye on dps with Madred's Bloodrazor. If they have low hp, they're not a problem, as you heal a lot of damage with your spells. Be careful with some of them, like an attack speed Kog'Maw with his W active, or an attack speed Jarvan with Madred Razor's.

This are the guys you should be really careful with:

Amumu

This little guy is your main problem. His spell Despair will bring you (and anyone without resistance) in a matter of seconds. The more hp you have, the more damage he deals. Plus, he keeps dealing damage with Despair even if you've casted Sanguine Pool (only if you stay around him).

Your team won't focus him, because Amumu usually is a tank, so try not going near him when he's crying.

Brand

Brand's passive deals magic damage that depends on your maximum hp. 2% per second for 4 seconds is 8% (duh). And 8% of 7000 is a LOT. So make sure you make the most of your speed to avoid his Sear and Pillar of Flames.

Nasus

Nasus is really hard to take down if he's using his ultimate, Fury of the Sands. Stay out of his range: being near him will make you suffer magical damage depending on your maximum hp and suffer his Siphoning Strikes. Wait until the transformation fades to engage him.

Vayne

Vayne is one of the few dps that doesn't care about your hp. In fact, the more the better. Careful with her Silver Bolts. I found one in a game and she didn't give me much trouble. Each time I had 2 charges of Silver Bolts and I was low on hp I casted Sanguine Pool under her and then nuked her without trouble.

Playing hp Vladimir, against all odds, is really fun. I love to see people trying to kill me and after I kill them they go: "Vladimir, hp?" and I tell the truth: ">1000 xD".

Be careful with your lack of resistance and champions who deal damage depending on your maximum hp. Use Sanguine Pool wisely and all will be well.

I'm trying to upload a screenshot of my last games. I'll do it when the European servers stabilize.

There is a mistake in the Item Section. The build considers that you'll keep one of the Amplifying Tomes instead of the boots, so you'll have more CDR than it's stated there. Also remember that the fields calculated at the beginning don't consider the Crimson Pact bonuses nor the charges of the Warmogs, so you'll have more hp and ap.