So after a bit of fiddling I managed to get this wonderful external case open without doing too much damage to the case in the process. Basically, the single, big, painted piece on the top of the drive is held in place with a number of clips. To get into the drive, you need to pry the bottom of the hard drive enclosure away from this upper piece starting at the end of the case with the connector ports. I managed to break the two clips at that end of the case but the rest still hold it together decently.

Another thing to realize is that the drive itself is held in place at the far end (opposite the SATA connections) by two sets of little plastic nubs. At first glance, it looks like these nubs are just clipped into either sides of the hard drive but they have other counter part nubs that stick into the bottom screw holes of the drive.

Bottom line: get a flat head screwdriver and pry the whole thing apart. 500GB 5400 RPM drive and a firewire enabled 2.5” enclosure for $120? I think it was worth it :)