I use an old leather case I had for a Palm V around about 2000 or so(can't remember). It is pretty good and I am used to it. I am not really out and about much on foot so it really just goes from home desk to office desk on the car seat. The n810 is about exactly the same size as the borders of the leather case so I guess it is possible for the sides to hit stuff but I am not really worried about the sides as much as the screen.

If I am going to be out and about on foot, I usually just pocket it and my debit card and ID.

Here are some pics. I really don't know if you can even buy one like this any more if you wanted to. I think it was OEM Palm as it has the Old P Dots logo stamped on front and says Palm Computing Platform