When I first saw this image of the DIY USB Hard Drive, the only thing in my mind was "How do I build my own?" After reading further, I laughed out loud. It's a trap.
Well, not really a trap, but a clever, clever mod. The first time you see it, you think some guy managed to figure out how to retrofit a hard disk with a USB plug. Unfortunately, that's not really the case. Imagine the look on your favorite techie's face, though, when you show them your custom-made portable storage.
Built by user "gmgfarrand" from Instructables, the DIY USB Hard Drive is actually just a bunch of flash storage crammed inside an old hard drive's shell. Yep, you rip out the guts out of a dead hard disk, throw in a multi-port USB hub, slip in as many flash drives as you can and close it up again. In this case, he used a four-port hub (because it fits perfectly inside the shell) and loaded each slot with a thumb drive. Voila - you've got a hard drive that can connect to your PC via USB without an enclosure.
If you plan to use this in a portable manner, make sure to glue or tape the hub inside - a bunch of parts making sounds when they shake it just gives the setup away. Also, don't hesitate to brag about how you can use your modded hard drive all day and not have it heat up. Tell everyone it's part of the mod. Because you're brilliant.