https://www.mobileread.com/forums/showthread.php?t=24800
This one will give you perfect protection.
Well I have my iLiad in this hardcover "executive" casing you can buy for it and always stuff it into my normal backpack together with my notebook and the paper books I still need through a day (yes ePaper didn't yet manage to completely replace those) Never had a problem so far. And I"m generally not gingerly with my electronic equipment.
The hardcover casing protects the iLiad well against impacts, however people say its still might be damaged by "twisting". However thats not somthing that normally happens in a backpack, or? Especially if its between other hard stuff. I never dared to take my iLiad and twist in my hands to look if its true, since it might be a 'oh, they are right, it gets broken if I do that' experience
I consider the most dangerous thing is the shoulderbag you get with the v2 iLiad, almost all "sudden breaks" without people dropping stuff on the iLiad were people taking it of the shoulderbag.