The best possible Master Transmuter deck I've been able to create. I honestly can't see any way to make it better unless they print more cards or change the ban list, so ALL SUGGESTIONS WELCOME!
By only playing 14 lands you can stack all sorts of goodies into the deck.
The Engine: Etherium Sculptors, Grand Architects, and Everflowing Chalices allow for colourless 6-7 drops on turn 3.
The Tricks: Master Transmuter, Thousand-Year Elixir, and Kuldotha Forgemaster allow for literally playing any artifact in your deck at will for 1 U or less. Transmuter also makes it very nearly impossible to kill anything that's on the board.
The Bombs: Six cards that deal with basically everything you can think of. Makes sideboarding really simple because you just slot out cards with little effect for their worst nightmares. Contagion Engine deals with bodies, the Spine deals with other permanents, Wurmcoil is never bad, Battlesphere gives you blockers, Sharuum brings anything they managed to kill back, and the Metamorph is another copy of anything, including threats to you.
Tezzeret is there for card advantage and a single shot kill, as laid out below.
Some cool things you can do!
T1: Darkslick Shores, Sleight of Hand
T2: Island, Etherium Sculptor, Borderpost, Mox Opal, Etherium Sculptor
T3: Island, Grand Architect, cast Blightsteel Colossus if you're using him or any other 12CMC bundle you want
T1: Darksteel Citadel
T2: Island, Everflowing Chalice, Borderpost
T3: Island, Grand Architect, Thousand-Year Elixir
T4: Kuldotha Forgemaster
On the end of their turn, sacrifice Citadel, Borderpost, and Chalice to play Myr Battlesphere, untap Forgemaster, sacrifice 2 Myr tokens and the Battlesphere to find Sharuum the Hegemon, returning Battleshpere. This nets you a 6/6 flyer (+1 for being blue), a Battlesphere that can swing for 10+6 (you can sac the tokens midcombat for more Forgemaster tricks) which is nicely over lethal damage.
NOTE: The above combo takes you from 5 artifacts to 10 artifacts, so if you have Tezzeret already in play you can use his -4 for lethal.
Transmuter, Thousand-Year Elixir, Mox Opal, and Spine of Ish Sah combine to make 1U: destroy two permanents.
I've only done this twice, but with enough mana (easy to do with Architects and proliferating Chalices) you can play Tezzeret, proliferate twice, use his -4, then next turn bounce Contagion Engine, proliferate, bounce it again, and proliferate again, to use his -4 once more.
Remember, you can put the artifact in play that you just returned to your hand because it's part of the cost. This also means that, besides Split Second, nothing can kill your artifacts if you have Transmuter ready. Boardwipes are a problem, but you Forgemaster a Wurmcoil and net some tokens, or for more hilarity, resolve a Darksteel Forge.