Awesome concept and deck! I will be back later with perhaps some recommendations, as I am at work, but for now just had to upvote.

I think that if you really want to consistently win by turn 4, you should get rid of walls and maybe add dual lands. Here's my deck, where you can find some ideas... I'll Take Your Life as Alternative Win Con.

I like the direction you went with your deck, while mine is more focused on this particular combo, I do agree that the walls could be replaced with something a bit more effective, they actually haven't been that useful in the games I've played. I don't think I'll require any dual lands, as I have not had a single issue with mana in any of the games I've played, but some Drowned Catacomb could only make it better :)Looking at yours, I'd say the walls are best replaced by things like Duress and Gitaxian Probe

Serum Visions , Sleight of Hand , and Gitaxian Probe are all cheap ways to tear through your deck and get your combo pieces. I would advise a play set of one of them over the walls. Also, I don't think the signet is needed i would take it out for another play set of the cards mentioned prior.

Cool deck. Crankmantle might sound better.

uses Pithing Needle naming Duskmantle Guildmage

Is there an problem sir?

Counterspell is not modern legal.

Love how this thing is play testing and may have to try it at my local modern night. Great set up and ability to get the cards you need, only one lands messed up the flow and it took till turn 7 to combo out.

@Drkpaw: Do you mean the Aqueducts? Those could be switched for checklands, scrylands, or fetches if you've got them, would probably help the speed. I only use them for mana density (it allows comboing out with less land).

Still play testing this one and enjoying it. Love the turn 4 wins but can say it reliable from turn 4-6. Every now and then one goes longer on the play test. Only thing I can say for those wanting to try something like this and for a bit more budget friendly replace Thoughtseize with Mire's Toll I don't think I've ever been without a swamp in play so always be able to trigger its ability and force a discard, though would replace them back to Thoughtseize when able as being able to pick a potentially dangerous card is better than picking out of 2 to 3 cards with toll.

@Drkpaw: Inquisition of Kozilek is another more effective budget option, though not quite as budget as Mire's Toll

Street Wraith if you prefer more cantrip over some transmute.

Was able to play this at my local tournament with Mire's Toll Vs another mill worked great. Delvers and Red burn got me, Thoughtseize would have been helpfull.

@Drkpaw: Yeah, burn is a bad matchup, Surgical Extraction and Extirpate help out with that (together with Thoughtseize they can wreck).

If you are worried mostly about instant/sorceries, Duress?

A bit expensive and a liability, but powerful combo. +1

I own a similar liability combo deck:

Awesome!

Bloodchief Ascension, for more combos?

4x Bloodchief Ascension also causes this combo to go off.

@thuzra,Saljen: Bloodchief Ascension does trigger the combo, but it's too slow to reliably get the quest counters on it in 4 turns, the slot is better left to dig spells.

I understand that this is a bit of a budget deck, though I would still recommend running Serum Visions over Sleight of Hand. The card is simply superior, and is worth the little bit of extra cash you have to drop for it. I would also consider running Spellskite over Apostle's Blessing, though I understand that this would make the deck far more expensive and therefore probably isn't within the deck's budget limit.
Another suggestion is to run 4xPolluted Delta and 4xHalimar Depths, cutting out 3xIsland1xSwamp, and both copies of Buried Ruin and Drowned Catacomb.
Again, potentially expensive changes, but changes that I think are well worth it for the deck.

Regardless of whether my rather expensive advice is worth it or not, I love the deck, and my personal opinion is that you sir would be next in line for the Dimir need to hire you as one of their Guildmages. I especially appreciate the use of a triggered ability as a win-con, meaning the deck can't be stopped by cards like Stony Silence and Null Rod. I would consider adding some form of enchantment removal, as this deck is only too vulnerable to Leyline of Sanctity. Perhaps a card like Esper Charm, though that would require splashing white...

Other than that vulnerability I love the deck. +1 from me.

Bloodchief Ascension tends to get removed really quickly, and it takes too many turns to charge up.

One way of doing infinite mill while getting around self-hexproofing like Leyline of Sanctity is Altar of the Brood + Myr Retriever + Heartless Summoning, but it's a difficult combo to pull off. Though with plenty of Gitaxian Probe and Serum Visions, maybe not all that difficult.

@TwoMagicDudes: That combo is worth its own deck, potentially setting off on turn two, and is much easier to pull off than you'd think. But the thing about altar of the brood is that it's almost exclusively a niche combo piece, and tends to give itself away in modern. Also, my combo can go off with Leyline of Sanctity in play, it just requires more creative triggering (I usually trigger on control decks by waiting for them to remove Duskmantle Guildmage and then activating him in response.)

Blackmail is also a very budget discard card.have you thought about Taigam's Scheming to get your combo out faster? ok, it's doesn't draw cards. but you can throw all the cards away if none of the top are the cards that you need

Taigam's Scheming looks very interesting i'm going to have to fit a play set in and see what it does.