I think they will release something for the ipad when the next game comes out... They made and released bungie mobile for the iphone and ipod toucch... But not the ipad... Holding out until the new game is released i bet.
As far as the vita, why not... The more tools they have for devs to work with the more aerospace will succeed. Go bungie!
I wonder if unreal tech will be supported, unless bungie releases thier own development set... Maybe that was the mysterious grognac or whatever from the vidoc.