This is Torterra (75 base SpA)
252+ SpA Life Orb Torterra Giga Drain vs. 252 HP / 120+ SpD Rotom-W: 187-221 (61.5 - 72.6%) -- guaranteed 2HKO after Leftovers recovery
252+ SpA Life Orb Torterra Hidden Power Ice vs. 252 HP / 0 SpD Landorus-T: 317-374 (82.9 - 97.9%) -- guaranteed 2HKO after Leftovers recovery
if 103 base SpA
252+ SpA Life Orb Torterra Giga Drain vs. 252 HP / 120+ SpD Rotom-W: 229-273 (75.3 - 89.8%) -- guaranteed 2HKO after Leftovers recovery
252+ SpA Life Orb Torterra Hidden Power Ice vs. 252 HP / 0 SpD Landorus-T: 385-458 (100.7 - 119.8%) -- guaranteed OHKO
252+ SpA Life Orb Torterra Earth Power vs. 56 HP / 0 SpD Shuca Berry Heatran: 343-406 (101.7 - 120.4%) -- guaranteed OHKO
Just ignore the leftovers, and imagine sitrus is there.
So basically, the toughest thing to deal with is not the special attack stat. putting it at a reasonable "Special Attacker worthy" number should solve many threats.
Increasing the special attack to beat the other tough threats: Aegislash and Scizor, would require racking up the special attack to insane levels though (over chandelure levels), which I am not yet sure is worthwhile. Scizor is a very different story though if this thing gets an ice/fire move, since that will allow HP ice+fire move/HP fire+ice move.
As for speed I want this thing to beat scarf Keldeo. It doesn't matter how rare that is because it will be important to kill. I get the feeling that I am not allowed to propose any base stat numbers here (?) but from calculations, at modest nature it will be extremely slightly above Kabutops. Which seems reasonable.
As for the bulk, I am torn between the choices of semi bulky nuker or super bulky threat killer. From using stoutland in singles (not sure if that is a fair comparison), I get the feeling that semi bulk nuker is much better, as threats are not the only thing you are killing. Putting not too much in HP is also good for gaining more from giga drain, though we could make it meet up to the 404 hp limit if anyone wants to build 252 hp sub build (?)
Oh and more physical defence than special. I like to hit my teammates in doubles so it would be good if this can take a few eqs from excadrill.
Therefore I propose Fantastic PT, Excellent ST, Poor PS, Excellent SS