tom.groenendijk

If I were you, I wouldn't put Sorin Markov in the main deck. The best ability for vamps he actually has is his second, and you're not using that realy. Sorin's cmc is equal to that of Bloodwitch, and I'd favor the latter. And since you're going for the attacking-vamp-theme, Coat of Arms? Boosts them like crazy if you have any in play.

Another thought on Hexmage: it also kills the enchantments that use quest counters. For example, you can annoy any deck using Archmage, Luminarch, Pyromancer, etc... Ascension, and delay your opponent's Landfall quest enchantments such as Quest for the Gravelord. And you can kill creatures with only +1/+1 counters on them to keep them alive. These also include Allies... So that's kind of great too.

Is it just me or aren't there any Tendrils of Corruption in there?
Oh, and, Vampire Hexmage.

So, how are you gonna make sure your foes won't just throw a 1/1 in front of your huge exalted attacker?

I'd add some unblockable stuff. Jhessian Infiltrator or Balmgiver is awesome.

Bant = Dueling Grounds. Protects against Bushwacker assaults, Vampires, Tokens, ... anything that stamps at you really. In my own bant deck (but without islands) I use it too, together with Topan Ascretic for blocking.

In this deck however I'm not quite sure if you want to keep attacking with 1 creature all the time. I mean, Jhessian Infiltrator is awesome with Grounds, but it's only good if it's exalted... So you need Asylum there still. I'd recommend a kick of Honor of the Pure. It gives +1/+1 to your lonely attacker... Well, I suppose you'd guess what i'd say to that.

And why not go with Dark Ritual? Easy to get Thrumming Stone on the field with those. And maybe some way to give all your creatures Haste. It's boring to sit out another turn with thirty 32/32 rats.

Oh, completely forgot to tell you I like the idea of this deck ;) Although, if you're not low on budget, you might want Elspeth, not for her soldiers but for her +3/+3 and flying on your exalted attacker.

You can lock any number of creatures, not 10...

t1: tap 10 with the first go
t2: tap another 10. Your opponent won't have an untap step so the previous 10 will still be tapped.
t3: tap another 10. Still, no untap step so your opponent is going to be annoyed with 30 tapped creatures.
t4: ...

You do know that Anowon makes you sac all of your zombies?

If you're going for the "I recycle all my nub vampires so i get zombies" idea, you could look at cards such as Carnage Altar. Makes the sacrifices worth their while. Squeezing in more Crypts completes your mana curve for the altar (you need to pay 3 mana aside from the sacrifice... crypts get better with more creatures in graveyard, so you should be fine with that). And put in 2 more Bloodghasts, and check wether you want Butchers of Malakir (7cmc), or Grave Pact (4 cmc, enchantment). The latter is earlier on the field and harder to kill (duh, it isn't a creature).

You should've made it B/W and add Tidehollow Skullers and Oblivion Rings etc.
These are pretty good at controlling your enemies' game, just like Faceless butcher etc.

Besides... Why the "destroy everything" artifact?

Please explain why Kalitas is good in this deck...?

You're playing white, so I suggest you bring in some Paths to Exile as well. It's better than Journey to Nowhere as it's 1 mana and irreversible. And G/W asks for Selesnya mana boosts.

Child of Night is awesome in life gain decks.. You might want to add him too.

Why Blade of the Bloodchief? Seriously.

Ravenous Trap is also useful in this deck's sideboard. Yes, it's black, but if you mill 3 cards in one turn, you play it for free, countering any revive-deck.
Also I'd recommend some unsummon, always useful to get the nagging creatures off the field if you're playing blue.

I suggest some ordering your library before casting Treasure Hunt. Then again, that's not in the deck yet. I suggest some ponders, sage owls, etc.

Also, I'm seeing you run high on black spells. How about a Crypt of Agedeem? Unless of course you were thinking of milling your own graveyard with shadowfeed.

How about the creature that says you win the game at >40 life?

It says "speed token". Doubling season is not speedy. At all. You need your mana to put this deck into work, none left to spend on that ench. The strategy says : build a sick amount of tokens and make them 4/4 trample". You don't need Doubling Season for that. Maybe Heartbeat of Spring. Speeds up your mana like Woot! And maybe even Nature's Will to do another Token Round whenever u attack.

Blade of the Bloodchief over Sadistic Glee.

The Kithin Heir card that says it gets +1/+1 for each kithin when attacking might be useful in this deck as well.
Also, what use is the Clachan?