Take a Standard USB Flashdrive, and cover it in hot glue for a unique clear case.
Step 1: Aquire a USB Flashdrive
You need to buy a flashdrive that is not retractable. These kind have move-able parts, and just make it harder. Any kind of any capacity will work. The final size is usually very close to the original.
Step 2: Remove the casing
Remove the case by cracking it open, if necessary, breaking it. If there is visibly a crevice around the drive where it snaps shut, take a blade and put it in. Twist the blade and the case should open. If this does not work, or there is no crevice, insert a knife into the area surrounding the USB plug. However, there is a chance if it goes in to far, it could damage the drive. Try to put it in as little as possible. If there are any stickers on the circuit board, carefully remove them.
There are different colored circuit boards depending on the manufacturer. The most common colors of the circuit board are Red, Green, and Blue.
Step 3: Cover USB Drive in Hot Glue
Lay down Parchment Paper on your work surface. DO NOT use anything else. (This includes Aluminum Foil and Wax Paper.) Choose which side of the Circuit board looks better, and start with this side. Cover the drive with hot glue completely, but make sure you don't go to far over the USB connector. Feather the edges or make it completely square. Wait for it to dry. AT LEAST 10 minutes.
After the glue is dry, pick up the drive and turn it over. Take the hot glue and cover that side. Try to get it as close to the edges of the other layer as possible. If necessary, you can shave the edges with a razor blade to match them up. If you shave too much, the edges will look dull and flat. You can run the edges of the drive over the tip of the glue gun to melt them and make them shiny again. Note that this will add a slight lip to the edges.