I would like some clarification. Does the rule state that the candidate must take those delegates via an election process or that he just must have a plurality. If it is the latter then Gingrich can become a nominee legitimately after the first round of delegates votes, if the convention is brokered. The second round five states can send their delegates to him. Therefore, Gingrich could be a legitimate nominee.
I believe the rules are that delegates can only vote for those nominated. The nominations come before the first vote is cast at the convention, so I suspect that he cannot be nominated without five states. I will try to read the full document tomorrow.