Zipe & Frone (Zip, Froh-nay) I cannot find too much about Zipe and Frone in the Book of Noga, but Tony Antelle has the following info:
"Zipe and Frone are conjoined twins. They are the ones who spread the Sands of Sleep throughout the land, and choose to withhold the Sands to those who are about to have an epiphany. Although they definately aren't, Zipe and Frone appear to be slightly Asian."
That sort of sums it up, I guess. Maybe I'm just not looking hard enough : )