Maybe something like this:
Infernape @ Life Orb
Ability: Blaze
EVs: 4 Att / 252 SpA / 252 Spe Naive/Hasty
-Nasty Plot
-Fire Blast
-Close Combat
-Grass Knot
...
Any thoughts?
Here are a few Grass Knot calculations;
252 SpA Life Orb Infernape Grass Knot (60 BP) vs. 252 HP / 4 SpD Azumarill: 177-208 (43.8 - 51.4%) -- 6.6% chance to 2HKO
252 SpA Life Orb Infernape Grass Knot (100 BP) vs. 4 HP / 0 SpD Cloyster: 455-536 (188 - 221.4%) -- guaranteed OHKO
252 SpA Life Orb Infernape Grass Knot (100 BP) vs. 252 HP / 4 SpD Assault Vest Donphan: 244-289 (63.5 - 75.2%) -- guaranteed 2HKO
252 SpA Life Orb Infernape Grass Knot (120 BP) vs. 4 HP / 0 SpD Mega Gyarados: 234-276 (70.4 - 83.1%) -- guaranteed 2HKO
252 SpA Life Orb Infernape Grass Knot (120 BP) vs. 252 HP / 4 SpD Mamoswine: 439-517 (103.5 - 121.9%) -- guaranteed OHKO
252 SpA Life Orb Infernape Grass Knot (20 BP) vs. 252 HP / 252+ SpD Rotom-W: 34-42 (11.1 - 13.8%) -- possibly the worst move ever
252 SpA Life Orb Infernape Grass Knot (80 BP) vs. 0 HP / 4 SpD Starmie: 221-263 (84.6 - 100.7%) -- 6.3% chance to OHKO
I was skeptic about Grass Knot when I saw your post, and though I checked to see if it was useful at all, it looks like it doesn't do a whole lot. It gives you a way to OHKO Cloyster (who fears Close Combat anyway and can usually be taken down by any special move at all,) and Mamoswine (which is kind of useful, but he's not a terribly difficult foe to force out by other means, and he too fears Close Combat.) Not guaranteeing an OHKO against Starmie is pretty bad, and the Pokemon you're 2HKOing otherwise can either take a huge chunk out of Infernape (if not OHKO,) anyway or, in Azumarill's case, 2HKO with Aqua Jet anyway. Rock-types like Tyranitar and Terrakion are hit harder by Close Combat, and using one of your STABs is preferable on all neutral targets.
So, yeah. Grass Knot doesn't look like its worth it.