Purple in Magic has been a major rumored color planned to be included in Planar Chaos. Of course, it was taken out before the set was released. Since then, there have been several players who have wanted to see purple appear in a set.
Here's a theory though... It was planned in Planar Chaos when time and space were being manipulated by rifts, and the Blind Eternities would have some connection to this. If spells, creatures, and artifacts from the past, future, and alternate timelines could pass through the rifts, then some must have had a connection to the Blind Eternities.