While SportShell Convertible ($45) is an updated version of a same-named case for the iPhone 3G/3GS, featuring a combination of a hard plastic shell with a soft neoprene armband, one rear piece for belt clip or armband mounting, and a second piece with a flat, opaque back, CustomShell ($30) is a little different. The design is similar, using two glossy hard plastic pieces that wrap around the iPhone 4's metal center while holding a rear cover…
