DedWards

Displacer does require a tweak of the mana base. Filter lands like Fire-Lit Thicket or Wooded Bastion, and / or pain lands like Karplusan Forest or Brushland will need to be added to pay for the {C} Displacer needs to flicker. These are a little more difficult to search for, and I've learned that Challenge gets slightly better with each fetch used (reduces number of lands in the Top 10).

Another idea I've come across, that I'm keen to try, is See the Unwritten. This would have a similar role as Chord of Calling in Collected Company decks.

Sh1t. Well, there goes that idea :|

Just realised this:
T1: land, Birds
T2: land, Evolve Birds into Eternal Witness, returning Evolution to hand.
T3: land, Evolve Witness into Reveillark, returning Birds and Witness to the battlefield, returning Evolution to hand.
T4: Evolve into practically you want.

Some looting would be a nice way to abuse Reveillark (would need to increase its quantity though).

Assault Formation - Gets you your "Toughness = Damage" without Doran being there.
Behind the Scenes - Effectively makes (almost) all your creatures unblockable. Works well with Doran / Assault Formation.

Like I said, "vulnerable to removal"

Played a few test games against the bot on XMage last night and here are my thoughts on the big threats:

Really liking Brooding Saurian as a replacement for Flickerwisp. Down side is it's VERY valuable to removal. Up side, I can cast it before Challenge and get my creature back at the end of the turn, meaning it doesn't have to be among the Challenge's choices. Definitely taking this to 3 copies, maybe 4, despite its vulnerability to removal.

I'm iffy about Boldwyr Heavyweights. It depends heavy on the opponent not having a big threat in his deck.

I've yet to even see Moldgraf Monstrosity, so I can't comment on it.

Creatures with etb effects aren't that great to reveal off the Challenge, especially since I'm not flickering anymore.

Wurmcoil Engine's lifelink has saved me more often than not. Almost enough to take it up to 4x.

Tentacruel and Blightsteel are perfect as 1 of's. They tend to win games all on their own. Blightsteel also allows Gruul Charm's "creatures without flying can't block" option assist in winning.

If a halfway smart opponent chooses Myojin of Life's Web off Challenge, I'll never get to use its Divinity counter.



Proteus Staff does look like a good option, good enough that testing is required. This would require blue, so maybe some Sage of Sage of Epityr to see whats coming? Actually, Sage + Staff looks like a great deck of its own.

Rough Gruul build taking into account what you suggested:

http://www.mtgvault.com/dedwards/decks/gruul-challenge/

Naturally, testing is required.

Was considering including Utopia Sprawl for abuse with Arbor Elf. Will need to up the fetch count and lower the dual count in favour of more forests. Could even include Fertile ground and Voyaging Satyr. Another way to regain control of your creatures is Gruul Charm and Brooding Saurian. Gruul / Naya opens me up to the Inferno Titans I have too, among other Gruul / Naya big beasties.

Solidarity of Heroes works wonders with Heroic creatures. The Heroic trigger will resolve before Solidarity of Heroes, then Solidarity double the +1/+1 counters there.

The flicker effect is to counteract the biggest down side to Dubious Challenge: the opponent gets to take one of them.

Had a few test games on Xmage last night (against the stupid bot). I had more misfires off Dubious Challenge than I'd like. Considering working in two or three Congregation at Dawn.

Fetch a mana dork, Flickerwisp, and a threat. Then arrange them so that the dork is on top to draw it, then Challenge into the other two.

You only seem to have one win condition, Steppe Lynx. And Felidar Sovereign seems like an odd inclusion, you're not gaining extra mana off the combo nor life, so it's instant win ability is kind of useless. I'd drop Felidar Sovereign in favour of another landfall card, like Retreat to Emeria.

Gather helps with checking legality. Sadly, the Vault isn't always correct on such matters.

http://gatherer.wizards.com

Testing is the biggest part of deck construction. I plan on buying what I'm missing during Black Friday this year, so only time will tell what exact numbers I will end up with.

Ezuri, Claw of Progress is also legendary, so having four in the deck can cause problems. With one out, any extras in hand become dead cards.

Lets (most) of your creatures attack without being blocked.

Tempered Steel: +2/+2 to all your artifact creatures. It's better than Spear of Heliod, but you may want to keep the Myr Galvanizers in.
Shrine of Loyal Legions: Gains charge counters each of your upkeeps and whenever you cast a white spell. Sacrifices to give you a ton of Myr.
Foundry Inspector: While not a Myr, makes ALL your artifacts cost {1} less.

I kicked out the Black in favour of the Blue.

Behind the Scenes?

Sol Ring is banned in every format (restricted in Vintage).