We've confirmed the voice-over donation and copy printed in the auction came directly from Bungie and says, "Voiceover [sic] will be recorded at Blindlight Studios in Hollywood, CA before May 15, 2007 or this package will have to [be] redeemed for Halo 4. Winner is responsible for transportation and accommodations to and from Hollywood, CA."
Executive Director of Hollywood Arts, Dylan Kendall, is excited by the auction and for the generosity shown by Bungie and many other companies. She says Tommy Tallarico assisted in helping get the auction items. Although we've confirmed that the Halo 4 line was written by Bungie, it could also just mean Halo Wars. So, Bungie really helped out Hollywood Arts big time. They wrote auction text that would get millions to view the page by just mentioning Halo 4 -- now that's how you hype charity!
[Update 1: Fixed information after speaking with Hollywood Arts' Executive Director Dylan Kendall]
[Thanks Master x 24]