Carrie Manolakos currently plays the standby for Elphaba in the 2nd national tour of Wicked. I found a recording of her singing Defying Gravity on youtube by accident. To be fair she's good. I like the fact that she sings the songs really well. I have yet to see any videos of her.
Anyway click here to listen to her singing THE WIZARD AND I.
For her website click here