During the IRC Q&A in
#Amiga.org Hans Joerg Frieden announced that OS4 will come out for the BlizzardPPC and maybe even the Pegasos2.
[10:59] <_4pLaY_> Hans-JoergF: Any chance we will see OS4 on Peg2?

and how about Shark and Blizzard versions?
[11:00]
4play: Peg2, sure there is a chance, but I don't make that decision. Blizzard: Affirmative. Shark: When we get a prototype.