The republicans also have "superdelegates". If I recall correctly there are 210 uncommitted delegates.
That's actually one of the two most likely outcomes for the GOP (in my opinion). If there are only 3 candidates left before Super Tuesday (i.e. Trump, Cruz and one moderate Candidate) the last moderate candidat will get all the moderate votes and likely win. If, however, the field remains too large for too long, then Trump will likely get a plurality of the delegates. But it is very unlikely that he will get a majority and certainly not enough to cancel out all the uncommitted delegates.
So this election cycle it is actually possible that the superdelegates/uncommitted delegates decide the candidates for both the GOP and the Democrats. (Although the chances for this to happen are much higher for the GOP.)
EDIT: Correction. I was misinformed. There aren't uncommitted delegates. Serves me right for actually believing Karl Rove sometimes knows what he is talking about. Nevertheless I doubt that Trump will get a majority.