Hey, I have been working on my own solution to this problem, and I think I've found a very workable solution. The key is to search for a case for the IPAD 1 -- these are the dimensions that most closely fit the boox m92. What I now use is this:
http://www.amazon.com/gp/product/B00...?ie=UTF8&psc=1 -- the Targus Zierra case for Ipad 1. I'm sure you'll agree the (discounted) price is right. It contains the M92 very well and gives excellent hard-shell like protection; I certainly don't feel any worries for the screen. It has a slot for the stylus-- I personally have the stylus rubber-banded to a regular pen for thickness-- and other random things. If there's one big downside, it's the weight; it really is quite a heavy case and at first I found this awkward, though by and by I've grown used to it. But I have a feeling that if you want protection you're going to have to deal with a heavier case.