The WWE has contacted several huge names from the past for cameo appearances at WrestleMania XXX. Some of those contacted were – The Rock, Ric Flair, Steve Austin, Shawn Michaels, Roddy Piper & Jim Ross.
The impression given is that The Rock will appear on the show in some form, but whether it’s live or taped isn’t known. People in WWE say The Rock will be on the show in some form.
WWE has also pitched some ideas to Steve Austin about appearing on the show. Austin has decided to make the trip to New Orleans, so that could be an indication that he’s accepted one of the ideas.
Source: WrestlingInc.com & Wrestling Observer Newsletter:
Wrestling News Blog 
I just want to hear that glass shatter one more time
And maybe he will dish out a couple of Stunners. Triple H would be a good candidate for one.
Exactly. i would also love to see Austin hit both Orton and Batista with the Stunner and drag Daniel Bryan over for the win. It would be the Reality Era’s version of Foley’s WWF Title win.
YES! that would be awesome!