Bought one of these in a smiggle store in australia, $14.95, in black to match the reader. You would have to take the reader out to use it, but in a bag it would give more protection than one of those soft slip in covers. Sizewise it's as if it was made for the kobo, it has a pouch inside that the kobo slips into, I would reccomend it and it's not expensive.
http://www.smiggle.com.au/SM_navIWCa...uct_Id=1602114