Jorma from HalfDome.net, the site that captures all the webcam images and compiles them into time lapse videos, looked through the archive from Saturday and found the video of the rainbow over Half Dome. He was also gracious enough to put the video on Vimeo so I could embed it here for everyone to see.
Thanks, Jorma.
Half Dome Rainbow from Jorma Rodieck on Vimeo.