PaulS
Touchdown! Greaser!
There's no rule that says two aircraft can't be on the runway at the same time. At a controlled field, the tower just has to assure that there isn't going to be a conflict.
I've done this a couple times at our delta, once the tower asked the airplane ahead of me to fast taxi to the end of the runway, another time I was asked to taxi to the end of the runway.
The worst is when you are on final at an airport, have the spacing perfect, and the guy in front of you stops on the runway. Usually gets an interesting response from the controller. I don't know what people are thinking sometimes.