I finally found a cover for my Cybook that is stable enough to be put it into my bag with other stuff without having to worry that the cybook will get twisted, squashed or otherwise damaged and does still allow me to read
while protecting the Cybook.
The best part is that it only cost
5€.
I took a notebook with the right size and height (A5, 96 pages) and cut out the middlepart, glued together the pages of the "frame".
I have to say that even though I own a standardcover for the cybook the selfmade one feels like a lot more protection for the simple reason that it cannot be compressed like the original one.
I'm not going to give up the standardcover for couch-reading, but for my way to university I feel a lot safer now, nowing that my Cybook won't get crunched between my other books.