I'm excited about the new
KF8 format!
Brown Bear, Brown Bear, What Do You See? is one of the ebooks featured in the Kindle Fire ads. The Kindle edition, made available on November 14, specifies "Available only on Kindle Fire." If that's the same edition that they show in the ads, that should be KF8, but I don't know for sure.
I'm on the email list to be notified when KF8 tools are available for publishers, and I have received no information to date, so I have no idea when it'll be widely available.