Use the Activesync device image as your disc drive icon
 

This doesn't have any practical purpose, but looks kinda cool :D

Copy the attached files (in the icon.zip archive) to the root of your SD card. When you plug your device into your computer under disc drive mode, your SD card drive will show up with the Touch Pro icon. You can see my Touch Pro is drive G in the screenshot.

This will also work with other storage devices if you change the icon file to whatever is appropriate for that device. Just replace the autorun.ico file.