If Romney doesn’t clinch the nomination on the first vote, then voting continues until a candidate receives the required number. Doesn’t matter whether he pulls out, concedes, or whatever.
In the 1920 Republican Convention, it took 16 votes for a candidate to be chosen - Warren Gamaliel Harding. His running mate was Calvin Coolidge. Neither was the man thought to be the candidate before the convention. They both went on to make history.
It happened before, it can happen again!
I suspect that Romney will be a really nasty loser.
In 1920 delegates were not bound to a single candidate. Apples and oranges. Full country primaries have changed the way we nominate. I admire your enthusiasm but you will have better luck playing powerball.