How amazing would it be to see Thom Yorke and The Gorillaz added? Thom Yorke could join Bjork and Jarvis on Stage for special appearances on Friday night. Then he could headline Saturday, bumping the Chili Peppers!
As for The Gorillaz...Damon is already going to be there for The Good, The Bad & The Queen. Shaun Ryder from The Happy Mondays could join in for DARE in a Gorillaz set.
I know these are pretty unlikely, but there are quite a few coincidences of connected artists being at the same festival.