I have a Belkin case and I am happy with it. However, my travels make me want to have as much protection for my K2 as possible, so I debated whether to get the official leather cover, or just use the Belkin. I did a Google search looking for a case that would store the K2 with the leather cover. I found a site called Waterfield:
http://www.sfbags.com/products/kindle/kindlecase.htm They have an item called the Large Sleeve Case; you can see it if you click on the little pictures under the big picture in the link above. It seems to accommodate the official cover, as well as providing a velcro closure around it. For me, it's the best setup I've seen. However, it doesn't ship until March 10th, so I don't have one in front of me. If I do decide to get one, I'll post pics and a review. I just thought I'd share in the meantime.