Polymorph
An Extended deck, by Akira Asahara
2nd place at a tournament in Chiba, Japan on 2010-12-12

Maindeck:

Instants
4 Cryptic Command (Not currently legal in Extended)
4 Mana Leak

Legendary Creatures
2 Emrakul, the Aeons Torn

Legendary Planeswalkers
3 Jace, the Mind Sculptor (Banned in Extended)

Sorceries
2 Duress
4 Polymorph (Not currently legal in Extended)
4 Ponder (Banned in Extended)
4 Preordain (Banned in Extended)
4 Thoughtseize (Not currently legal in Extended)

Tribal Enchantments
4 Bitterblossom (Not currently legal in Extended)

Basic Lands
4 Island

Lands
4 Creeping Tar Pit
4 Darkslick Shores
2 Drowned Catacomb
1 Khalni Garden
4 Misty Rainforest
1 Murmuring Bosk (Not currently legal in Extended)
4 Mutavault
1 Sunken Ruins (Not currently legal in Extended)

Sideboard:
4 Wurmcoil Engine
2 Consume the Meek
2 Doom Blade
2 Smother
2 Jace Beleren
1 Duress
2 Infest (Not currently legal in Extended)