Just bought my kobo and needed a case and seeing as not much is available yet is was looking around the house.
I pulled on of the old Kodak plastic binders designed to hold the APS film (remember those). This one has slots for old "canisters" of film but also a open side for slipping pictures or negatives in.... it's almost a perfect fit for the kobo and presto!!! a hard cover case (less than an inch thick).
Works for me in the short term!