Currently we can flex and bend OLED screens, but we won't be folding them, and even if we could right now, would you like to purchase a $40,000 iPod? When OLED first came out for consumers, it was like $3000 for an 11 inch screen, and now you want to fold it.
To be honest, by the time these are available, I doubt they will be iPods in the fashion we think of them now.