was down in the states on the weekend and picked this cover up from B&N:
http://gifts.barnesandnoble.com/Sinc...598823/?itm=35
although designed for the nook, the "elastic corner system" and "molded bottom cup" still hold the kobo firmly in place. the molded bottom cup does not interfere with using any of the buttons. there is a cutout on the bottom to allow for the usb cord. this particular version appealed to me over the other cover options due to the rounded corners - which i thought mimics the kobo design nicely.
a little pricey at $30US but it looks great and doesn't add a lot of bulk.