Apologies for double posting, but I've been experimenting with SI this weekend and I think there is room to innovate, one of the things that occured to me when reading thru' the thread is that Land Grant is a liability compared to Fetch Lands and that Goblin Charbelcher isn't actually worth weaking your manabase to counter magic or playing a maximum of 6 "Land" between Bayou, Dryad Arbor and 4 Land Grant. If you replace Land Grant with Fetchlands and increase the number of Fetchlands beyond 4 and the number of Bayou beyond 1 you can increase the number of initial mana sources, land drops and culling targets in the deck, which makes it both more consistent and resilient. The problem comes in where you start chaining Draw 4s and realize Culling the Weak is dead after your first Dryad Arbor is sacrificed or after you've played Bayou and can't make a second land drop for Dryad Arbor on the same turn, which is where Summoners Pact comes in to make the extra creature drops. Then what occurred to me was that multiple Elvish Spirit Guides take up more space than they're really worth as accelerants compared to adding more and more lands and we could cut down to 1 ESG and 1 Cutter and with a combination of 11 forests and 5 virtual cutters that Burnt Offering is really close in power to Culling the Weak when you can reliably get down the forest.

So I'm messing around on apprentice and came up with a build that tests some of the possible configurations,

4 Tendrils of Agony
1 Ill Gotten Gains
4 Infernal Tutor
4 Cruel Bargain
4 Infernal Contract
4 Dark Ritual
4 Culling the Weak
4 Burnt Offering
4 Summoners Pact
4 Skyshround Cutter
4 Lion's Eye Diamond
4 Lotus Petal
4 Chrome Mox
8 Fetchlands
3 Bayou

Imagine the original spanish inquisition just switching out robots for cutters and disruption for lands and I think you can get close to a deck that plays, Bayou, Cutter and either Culling the Weak or Burnt Offering as its first turn play pretty consistently. You could integrate other elements into the deck by SBing in 4 Cabal Ritual, an Elvish Spirit Guide, a Dryad Arbor, a Deathrite Shaman and SBing out 4 Burnt Offering 3 Cutters in order to increase the utility of the fetchlands and summoners pact or cut pact altogether and try running Xantid Swarms in match ups with minimal removal spells in order to hit a double land drop, attack and sac Xantid Swarm and then hold the B/G mana back for possibly needing to cast another Xantid Swarm for a sac outlet.

I'm not really sure how well the idea is going to hold up, but I think it's kind of interesting to just concentrate on Tendrils so you can drop Land Grant and try to increase the number of initial mana sources and tutors for Dryad Arbor and I don't think I've seen anybody suggest going this route before.