I appreciate the thoughts on case vs. sleeve. Perhaps sleeve isn't exactly communicating what I want to do. I want something that will, in fact, protect the device, but on which the device is easily removed to actually do reading from. A thin piece of fabric wrapped around the Kindle obviously isn't going to do much, but I'm not sure a case where the Kindle is attached inside is necessarily the be-all, end-all solution.
A nicely padded, zippered pouch (to ensure pressure protection as well as not flying out of the sleeve if moved suddenly) seems to be the best of both worlds for what I'm looking for.