Yeah, If I were gonna do it, I'd do it Hermit Druid. Grindstone/Severance won't work as good as you think because you'll still bump into the occasional grindstone or severance as you try to flip stuff over, and so by the time you set it up, you'll probably need 5 or 6 activation before you can flip your deck over. Hermit Druid can go in one pop. Actually, a funny way to work the Druid might actually be to run 2 or 3 swamps in your deck, that way your second turn druid can just go get you the next two lands you need to actually cast the Mortal Combat.
If you want this to be extended legal, however, you might need a different approach because they just banned Hermit Druid in January.
For this, Buried Alive is always good, and maybe you could work some massive black mana combo, (read: Cabal Coffers), so you can just cycle Undead Gladiator a bunch of times during your upkeep. Weeeeeeeee.....
Obviously anything that flips your deck over or draws/discards is good, Careful Study, Merfolk Looter, Brain Freeze, etc.