Well I've been working on building a form of Dredge since sometime in September, I wanted something decently cost effective (didn't turn out quite that way) and something that was not done. I have spent months going over this and changing it and finally I present to you a new dredge build that has not yet been run, created by me that at World's Collide play testing has stood up to some good legacy decks and won ...
Zombie Dredge
Creatures (23)
x3 Putrid Imp http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=34470
x4 Narcomoeba http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=136140
x4 Ichorid http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=35923
x4 Stinkweed Imp http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=193870
x2 Golgari Grave-Troll http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=88960
x2 Golgari Thug http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=88994
x2 Flame-Kin Zealot http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=83562
x1 Iona, Shield of Emeria http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=190407
x1 Akroma, Angel of Fury http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=122432 (Angel of Wrath works also)
Spells (15)
4x Dread Return http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=116721
4x Cabal Therapy http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=34789
3x Careful Study http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=29727
1x Breakthrough http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=29927
3x Tome Scour http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=191598
Enchantments (6)
4x Bridge From Below http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=136054
2x Zombie Infestation http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=29957
Lands (16)
4x Watery Grave http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=83731
3x Blood Crypt http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=97102
4x Scalding Tarn (Blue/Red Fetch)
2x Misty Rainforest (Blue/Green Fetch)
1x Cephalid Coliseum http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=29903
2x Island
Sideboard (Still a work in progress)
x1 Dryad Arbor http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=136196
x1 Life from the Loam http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=89001
x2 Forest
x1 Ray of Revelation http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=34199
x2 Ancient Grudge http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=109751
x1 Darkblast http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=87922
x1 Malfegor http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=185812
x2 Leyline of the Void http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=107682
x2 Drowned Rusalka http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=107687
x2 Telepathy http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=189910
Key Differences
There are some big differences in my Dredge build in comparisson to other builds you may see on the net.
1. I run only 2 Grave-Trolls, being the biggest dredge piece this may seem rather insane but having the 2 extra Thug's in play gives you more to feed to Ichorid who is your win condition and with Tome Scours and my key addition of Zombie Infestation it's much easier to come upon dredge cards then before.
2. Zombie Infestation??? Yes a two drop enchantment that allows you to start discarding cards and building up an aresenal even earlier. If you draw 2 mana producers and an Infest in your opening hand by turn two you have two zombie tokens and your dredge is running full speed. I have found this combined with actual land actually can speed dredge up far more then you ever thought.
3. More win conditions main board. Most dredge builds run 1 Flame-Kin, 2 Dread Returns, and 1 other alternate win condition. This build allows you to bring out two powerful creatures, Iona/Akroma as well as have two chances to bring back the Flame-Kin to pump out wins with the zombie tokens you will be amassing.
4. Note this deck uses different lands then other dredge decks do. This allows dredge to actually start an earlier game as you can play first if you want and bait out opponents or keep them surprised to what you are doing, there are more ways to discard or mill yourself into dredge pieces.
5. The addition of Tome Scour main board. Most dredge decks run a ridiculous 4 mana card that can flashback that doesn't work nearly as well as milling yourself. Tome Scour can be removed to add more creatures like Street Wraith, Grave-Troll if you would like, but I wouldn't advise it. This card is a key new addition to the dredge build.
Anyway this is my deck, it may look weird and off the beaten path but I have proxied other dredge builds and I do think this is the fastest build I have seen. The sideboard may need work and it may still need a way to come up with some answers for certain decks, but it isn't easy to beat and the ability to use Iona, Akroma, or Malfegor in the deck I feel makes every game different.
Weakness : Remove my graveyard at a key point and I am done.