I doubt it will ever happen again. I could maybe see a match being offsite if there were some lame gimmick attached to it like WCW used to do all the time (ie: on the roof of a building, in a graveyard, in HHH and Steph's bed, ect.).
You lost today kid, but that doesn't mean you have to like it.
Idk call it a crazy idea but I think its possible to have one wrestlemania take place in London and another one take place in the states on the same day only problem is WWE does not have a big enough roster at all to pull it off you would at least have to have 9 matches for each location.