Levenger Compact Circa Zip Folio.
The inside dimensions are perfect, it's like it was made for the Cybook. This allowas me to zip it up and toss it in my purse or backpack.
And some of the colors are on sale cheap, even 2 of them on Ebay.
It is really no thicker than it needs to be. Then only thing I'd change is having the hinge at the top.
I just used two strips of velcro that don't interfere with the reset, battery door, or label on the back. The same Velcro they use on PDAs.
Gladtobemom