The fact that there is no 40k analogue is extremely disappointing to me. Berzerkers or Chosen on juggernauts should definitely be a thing. Prior to the release of Khorne Daemonkin, during the rumors phase, I had all my digits crossed that they would actually create this unit for the new codex.
Obviously, that didn't happen. WELL SHIT, what is one to do when our beloved collectible-miniatures-company who coincidentally makes rules for those miniatures falls short of the mark? Forge our own narrative, of course! /takes a swig of punch
I've created rules for 40k Skullcrushers, but I'm still refining them. Sooner or later I'll release those rules.
In the mean time, I've simply decided to use power armored Khorne dudes on juggernauts as bikers. Sure, their stats aren't as impressive as they would be if they actually rode the coolest beasts from the warp as their chosen mounts, but at least this way the rules already exist and they're good to go.
The majority will be armed with meltaguns (infernus pistols as meltaguns) and used in Gorepack formations from the Khorne Daemonkin codex.
Here is my first attempt, a mock-up using various parts from the Skullcrushers kit, Chaos Space Marines kit, infernus pistol from Death Company, "power axe" which is really a chain axe (GG Forge World) from the FW Cataphractii weapons kit: