DriveBox mini is the answer. Protect bare 2.5-inch drives while storing or transporting. Its easy-to-open case gives you ready access to the drive when you need it.
The case features top-side access to the drive SATA or IDE pins. It's not meant to serve as a permanent enclosure, but if you're in a pinch and want to protect the drive circuitry while you access a few files with a cable, this case can allow it.