Garett Young, bad combo deck aficionado, recently made the Top 4 of a Modern Premier IQ with his take on Griselbrand in Modern. It has some similarities to decks that Todd Anderson and I have worked on, but ultimately, it's got a few new things worth highlighting.
First of all, Garett actually performed well in the tournament! He was undefeated in the swiss, and it looked like his deck was firing on all cylinders. While Griselbrand may have made a Top 8 here and there, this is probably the best showing the deck has had.
Secondly, Garett's version utilizes Necrotic Ooze to give the deck a little more consistency. Todd tried to do the same thing, but it never really caught on. Zombie Infestation gives you another discard outlet and something to do once you activate Griselbrand, Lightning Axe and Soul Spike keep the board clear, and Grisly Salvage finds your missing pieces. All of these things lead to having a more consistent deck overall.
Finally, Garett has a semi-transformational sideboard plan with Pack Rat, which I think is a great idea. If you're interested in the deck, you can watch his Deck Tech here.