Here's a Mana Denial Rofellos Deck I've been working on. I haven't been able to play too many games with it because people usually don't want to play more than a game or two

So it's a little unrefined.
General:
Rofellos, Llanowar Emissary
Mana1 Mox Diamond
1 Lotus Petal
1 Sol Ring
1 Wooded Foothills
1 Windswept Heath
1 Verdant Catacombs
1 Dust Bowl
1 Wasteland
1 Strip Mine
1 Yavimaya Hollow
26 Forest
Mana Denial1 Creeping Mold
1 Desert Twister
1 Woodfall Primus
1 Reap and Sow
1 Mwonvuli Acid-Moss
1 Acidic Slime
1 Mold Shambler
1 Mishra's Helix
1 Trinisphere
1 Plow Under
1 Stunted Growth
1 Primal Command
Mana Ramp1 Kodama's Reach
1 Skyshroud Claim
1 Explosive Vegetation
1 Hunting Wilds
1 Nature's Lore
1 Three Visits
1 Yavimaya Elder
1 Wood Elves
1 Krosan Tusker
1 Gauntlets of Power
1 Garruk Wildspeaker
Bid Stupid Guys1 Patron of the Orochi
1 Regal Force
1 Nemata, Grove Guardian
1 Sundering Titan (also mana denial)
1 Vigor
1 Chameleon Colossus
1 Crush of Wurms
1 Kamahl, Fist of Krosa
1 Cloudthresher
1 Panglacial Wurm
1 Primalcrux
Utility Guys1 Eternal Witness
1 Masked Admirers
1 Stampeding Wildebeests
1 Dosan, the Falling Leaf
1 Quirion Ranger
1 Indrik Stomphowler (is usually mana denial)
1 Wickerbough Elder (same)
1 Seedborn Muse
1 Masticore
1 Genesis
Draw/Tutor1 Sylvan Library (lol 40 life)
1 Soul's Majesty
1 Worldly Tutor
1 Survival of the Fittest
1 Natural Order
1 Tooth and Nail
1 Memory Jar
1 Chord of Calling
1 Harmonize
1 Primal Command*
Everything Else1 Sword of the Paruns
1 Umbral Mantle
1 Lightning Greaves
1 Staff of Domination
1 Goblin Cannon
1 Squall Line
1 Mindslaver
1 Regrowth
1 Restock
1 Crucible of Worlds
Notes~Umbral Mantle, Sword of the Paruns, or Staff of Domination along with Rofellos is infinite mana. Umbral Mantle also makes Rofo arbitrarily large, and Staff gains infy life and draws your deck.
~Many of the cards have a lot of different functions. You'll notice that most of the LD can do other things too if that plan isn't going to work for a particular game. A lot of the utility creatures give you a lot of decisions as well. Even most of the fatties do things other than attack (and those that don't are REALLY big. Primalcrux is usually at least 14/14 by the time he comes down).
~My favorite play of the deck is Primal Command on turn three, bouncing a land and getting Eternal Witness. Next turn (assuming you've hit all your land drops, and Rofo is still alive) you have 8 mana to play EW getting back Command and play it, bouncing a land again and getting Stampeding Wildebeests. Then just play Primal Command every turn, and you can start shuffling the lands in using the third Comman ability and cut them off lands completely.
~ When Zendikar comes out, two Forests will turn into Misty Rainforest and BG Fetch, pretty much just for Panglacial Wurm. I'm not even sure if it's good, but it's really fun.
~Haven't tried out Gaea's Cradle yet, which seems like an almost auto-include in the other Rofo decklists I've seen, but it just doesn't seem that good. I want to make sure that I have enough Forests early game to power up Rofo, and by the time I have enough creatures to make it worth it, Rofo's making so much mana it doesn't even matter. The average CMC of the creature in the deck is almost 5, and that's including Crush of Wurms as 6 creatures. So it's tough to gain any advantane until very late.
~Nature's Lore, Three Visits, and Skyshroud Claim are all "free" (net you the same amount of mana), as long as you don't tap Rofo to cast them (and if you have him in play, of course).
~As the title suggest, I designed this deck to focus on duels, as the LD strategy can't really compete with multiple players. That said, since most of the LD is vesatile, I think it would do alright in a multiplayer scenario. You'd just have to alter your playstyle. Cards like Mishra's Helix and Plow Under would get markedly worse, but Creeping Mold and Acidic Slime can just kill that problematic enchantment or artifact instead. Plus, you have a lot of big stupid guys that you can play really quickly. The biggest thing I'd fear in a mutliplayer game would be mass removal.
Comments, Questions, or Suggestions?
EDIT: Added some Zen cards. Another Forest will turn into a Misty Rainforest when I acquire it.