It is common knowledge that a script treatment was created for a fifth Bionicle movie. For those who have not seen it, it can be found here:
Since Bionicle was cancelled before this movie came out, nothing in the treatment was considered to have happened, and the official ending contradicts the existence of the treatment.
But, after digging in the Greg Archives for something unrelated, I came across this, from 2010:
(Questions 5 and 6)
In this, Greg seems to confirm that the events of the script treatment did indeed occur in an Alternate Universe, though the new names are still not canon.
Did he later refute this claim, or should the script treatment be added to BS01 as the “Valley Of The Maze Alternate Universe”?
EDIT: This question has been asked here before, and Greg stood by his statement, as recently as February of 2019:
So it seems some stuff needs to be added to BS01.