I do not think that we will ever see any other ranked then Summoners Rift. (At least I hope so).
You see, every new champion and every patch and balances are focused on Summoners Rift. Why?
Because Summoner Rift is League of Legends. It is the map that is mean to be played competitively. It offers a space for different kind of tactics, that is a balanced map.
Of course there is Ranked for TT, because it also offers space for plays but in comparison to SR it is still weak.
Dominion on the other hand is simple map that is not much balanced and champs are not designed to work there as good as on SR and TT.
and ARAM... well it is not even nearly possible for it to have ranked. Because you have to always have chance to win. And randomly assigned champions do not support that idea.