Of course, it's not really feasible in commander since you can only have a single copy. Sure, it's POSSIBLE, but it's really hard. First you have to clone your commander (something anyone not blue will have a hard time with) and then you have to get it into your hand somehow...by that point, it can't possibly be worth the effort, right?
Well, probably, but I want to do it anyway.
So there's three steps to the combo:
Step 1: clone Korlash and bin the original.
Step 2: return Korlash to hand from grave.
Step 3: Grandeur! Mission accomplished!
That might not sound super exciting for a glorified explosive veggies. What makes this worthwhile, though, is that if you've got a way to do step 2 repeatedly, you can easily enable grandeur not once, but over and over. For this reason, the MVP of the deck is Phyrexian Reclamation. For 2 mana, you can get 2 tapped swamps, as often as you can pay for it. You can see how this might get out of hand pretty easily.
How it wins, ultimately, is a little boring - mostly via Exsanguinate or Torment of Hailfire. But there are other more fun options! Dread Presence, Ob Nixilis, the Fallen, or a big lifelinky tramply korlash clone can all be some good clean fun.
Anyway, here's the list:
I spent a bunch of time thinking through the other grandeur commanders, and I think the only other one that would work at all would be Baru, Fist of Krosa, almost entirely thanks to Paleoloth which goes infinite with him. I opted to go with Korlash instead, though, because I think Baru will be a lot less interesting to play - you tutor for paleoloth (and probably Mirrorpool since the other clone options are hard for green to tutor) and then you win if you pull it off, there's no real middle ground. With Korlash you might end up just getting 2-4 free swamps a turn, or Exsanguinating for a large, nonlethal amount, so it seemed more interesting.
EDIT: just had an amazing brainstorm - Field of the Dead is absurd with Korlash! It sounds hard to enable, but Korlash can tutor nonbasic swamps like leech-ridden and cottage, plus you've got the snow and non-snow versions of swamp. Plus field itself, you only need 2 other land names and Korlash gives you everything else on a silver platter. From then on, every cycle of Korlash nets you 2 zombies for free! Insane!