MTG Salvation

You should update the first post with a list of all the needed characters/elements and possibilities you've found so far.

You could almost make the main cast out of Planeswalkers and Reaper King as the Scarecrow Commander

Tin Man - Karn Liberated
Lion - Ajani Goldmane
Good Witch - One of the Elspeths maybe
Bad Witch - Liliana Vess or one of the Chandras
Oz - One of the Jaces

I know they're stretching it some. Just brainstorming.

But look at google images for the city of Oz and tell me it doesn't look like Serra's Sanctum.

Recross the paths is the closest thing I can find to a yellow brick road so far. Meh.

edit... Oh! You totally need to paint a pair of Lightning Greaves red for the ruby slippers. In fact, if you really wanted to go all the way with this, you could use the Set Editor to make custom art cards for the characters. That way Jareth or Ajani would actually be the art from the movie and greaves really could be the ruby slippers, etc.

Don't forget you'll need Toto, a Yellow Brick Road, and some Evil Flying Monkeys, as well as the Wizard Himself (any cards with a man behind a curtain?)

What to use for them, I have no idea. I will keep an eye out though.