My choices for casting:

Ranma as Dorothy ("Hey, why I gotta wear a dress?!")

Ryouga as P-chan/Toto ("Bwee!" [Die, Dorothy!])

	(These two are fighting in the house when it gets picked up by 
the twister, and fall into a magic pool as they step out...)

Kuno as the Scarecrow ("Oh, if only I had that gray matter which lesser 
mortals so flippantly refer to as a brain!")

Nabiki as the Golden Woodswoman ("Coooiiinnn....Cooooiiiinnn....")

Genma as the Cowardly Panda ([I'm just a lovable panda!])

Nodoka as Auntie N ("Ranma, time for your chores!")

Kasumi as the Good Witch ("Why, you've had the power to turn back into a 
boy all along, Dorothy.")

Rouge as the Wicked Witch ("Have some fire, scarecrow!")

Pantyhose Tarou as the Flying Minotaur ("Damn magic hat.  You just wait, 
witch.  One of these days, you'll turn your back...")

Shinnosuke as the Oz Guard ("Umm....are you people still here?")

Happosai as the Wizard of Oz ("Bring me the panties of the Wicked Witch 
of the West!")

Akane, Ukyou, Kodachi and Shampoo:  Munchkins ("Now that you've killed 
the Wicked Witch of the East, you're engaged to all of us!")


SKJAM!