I would add one suggestion that i very important to a small minority of users but I feel would actually work well and be enjoyed by users who do not need this modification directly.
But those of us with hand problems generally have problems gripping things for long periods, or as in my case, even shorter periods. We drop things without warning. Some of us have simply stopped reading because we cannot hold a simple paperback book open.
What would make a HUGE difference is to have a hand strap across the back. It could be in the form of a flip out handle style similar to the 'kickstand' on the Nokia N800. It could also be non-integrated to the device but instead part of a 'skin' (someone mentioned Camera Armor which is amazing stuff) that wraps around the back of the device. Currently TabletKiosk offers the exact style of skin w/back hand strap on the back which allows one to easily hold their slate PC's in one hand while writing on the device with the other. Since I am butchering the concept here is a link to what it would look like:
http://www.tabletkiosk.com/tkstore/p...&idproduct=235
You can see there is an elastic hand strap on the back...this would would GREAT on an ereader device. It also would go a long way to reduce the chance of the reader being dropped while being used by anyone. The ergonomics of single handed reading would need to be considered when designing the skin/strap solution. But I am sure that can be solved by your design folks pretty easily. I will say if the Kindle I bought (and hate completely for several reasons) had this sort of accessory I might consider using it a bit instead of reading outside on my OLD Sony Clie w/transreflective display.
I also mentioned a flip down 'kickstand' integrated "stand" like is found on the Nokia N800. I use this not as a stand but rather as a brace to allow single handed reading on the N800. It works just fine and I have yet to drop or feel pain as a result of holding the device for an hour or more. Still I think for an eink device I would prefer the skin with adjustable elastic hand strap across the back...and access to page turning buttons would be a nice bonus for single handed reading.
Sorry if this was a tad scatter brained but I think i got the idea across...I will only add a lot of folks who read the most have physical limitations and reading might be the only recreation they have other than TV so anything that allows access to reading more would be a good thing.