I love my N800 tablet computer, but the included slip case is very poor. It protects the screen from scratches but nothing else. It doesn’t even close, so picking it up facing the wrong way is an invitation for the computer to slip right out onto the floor. Fortunately the N800 is built fairly tough, but still a case that encourages computer dribbling is not a good idea. Various camera bags are expensive and the wrong size.
My son pointed out that a Nintendo DS Lite case is just the right size to accommodate an N800. I got one at WalMart for $20. It has light foam padding, a velcro closure, and a carrying strap. It is labeled "Nintendo DS(tm)" which might attract sideways glances at business meetings, but might also cause a pickpocket to pass you by. From my son’s point of view the best part was that it also came with 3 extra DS stylii and 2 or 3 game cartridges, which were his reward for the tip.
I see there are also hard shell cases for the DS Lite which may also fit the N800.