Funny, i was working on a similar deck yesterday. Not finished, but feel free to get inspired and leave a comment:http://www.mtgvault.com/mrlinddk/decks/white-blue-green-exaled/
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Oh and Master Transmuter. And perhaps Metalworker.
Great deck. A few suggestions:Miren, The Moaning Well would fit perfectly. If you are low on life you have a way back in the game.Proliferate is a great combined with modular. Throne of Geth would be great.With Welding Jar you don't run out of creatures to sacrifice.I don't know if Illusionist's Bracers works but if it does, you double your counters when you sacrifice you a creature.
Nice and straight forward!Consider adding Mirrorworks, which is almost too good with Kuldotha Forgemaster. Since you don't spend mana using Kuldotha Forgemaster, you can quickly add a couple of copies.http://www.mtgvault.com/card/mirrorworks/MBS/