While it wouldn't actually be Wrestlemania, there are plans underway to do a Global Warning 2 show at the MCG next year. I can only imagine the card they would have to put up to sell 100,000 tickets. I'll start saving now just in case.
http://www.prowrestlingsheet.com/global-warning-ppv-wwe/#.WinlP0rXaHs
http://www.prowrestlingsheet.com/global-warning-ppv-wwe/#.WinlP0rXaHs