As a more user-customizable version of its 5G Quartz Case, Pacific Rim Technologies' Quartz Shield for the second-generation iPod nano ($20) comes with five sets of colored side inserts -- blue, green, pink, black, and gray -- which slide out of the clear plastic shell, enabling it to open into two pieces for insertion of your nano. You then close the shell and re-insert your preferred side pieces to lock the case closed.
