This is an interesting idea, I can find those Dell D-Series floppy drives everywhere, and working with one of those it shouldn't be too hard to pull one apart for the internal drive and circuitry, mount that inside the case and then cut a hole in a floppy bay plate or something so it can be used. The reason for keeping the Dell circuitry is that it has a USB port on it, allowing them to be used as external drives as well as in a laptop. Making a cable from the on-board USB header to the drive wouldn't be too hard, even less if you pull a USB header off an old case and then use a plain cable.
I need to try this when I get home, I've been needing a floppy drive and external is a bit of a pain.