I think if you added a temprank command, it would allow server owners to see if someone would qualify for op, while not making a new rank. If you added this, you should add a time limit to it, and make it go away when they sign out.
Ex. /temprank [player] [rank]- Ranks [player] to [rank] until he/she signs out.
/temprank [player] [rank] [time]- Ranks [player] to [rank] until [time] runs out.