A vacation to Australia to pick up the covers would be good.

Although we are sweltering in heatwave of 42ºC (107.6ºF) days here in Sydney, while Queensland deals with the aftermath of the floods last month and now has a Category 5 cyclone about to hit.
My daughter bought a black lighted cover yesterday at our local Borders and it was the last one in stock. They said they didn't know when they would have any more. They are still in stock on the Borders Australian website though -
http://www.borders.com.au/sony-readers