I played against someone at GP Prague who was playing a slightly different version of Atarka Red. It had [scryfall]Self-Inflicted Wound[/scryfall] in the sideboard to fight all the Abzan Aggros (or Hangarback Abzans in WotC coverage nomenclature). Seemed like (and he admitted it too) he was streching his manabase just a little too much by having the one Swamp in the sideboard with a set of [scryfall]Bloodstained Mire[/scryfall]s and [scryfall]Mana Confluence[/scryfall]s in the main.

However, in the world of Battle Lands (or Tango Lands or whatever), this isn’t such a bad idea. Couple of [scryfall]Smoldering Marsh[/scryfall]es that doesn’t even have to be in the sideboard can do the same since you want to play all the fetches that can get you mountains anyhow.

Of course, many of the cards in the deck (most notably [scryfall]Foundry Street Denizen[/scryfall], but also [scryfall]Lightning Strike[/scryfall] and [scryfall]Goblin Rabblemaster[/scryfall]) are going to rotate out, so the deck as a whole requires some retinkering.

[deck]
[creatures]
4 Abbot of Keral Keep
4 Monastery Swiftspear
4 Lightning Berserker
2 Mardu Scout
3 Zurgo Bellstriker
1 Scab-Clan Berserker
[/creatures]
[spells]
4 Dragon Fodder
4 Hordeling Outburst
4 Atarka’s Command
4 Wild Slash
1 Become Immense
4 Exquisite Firecraft
[/spells]
[lands]
4 Bloodstained Mire
4 Wooded Foothills
4 Cinder Glade
1 Smoldering Marsh
8 Mountain
[/lands]
[sideboard]
4 Self-Inflicted Wound
3 Scab-Clan Berserker
3 Smash to Smithereens
2 Barrage of Boulders
2 Goblin Heelcutter
1 Mardu Scout
[/sideboard]
[/deck]

The manabase is still a bit awkward, but at least there’s 16 ways of getting a mountain untapped in the first turn despite three (potential) colors.