Sold in three different versions at the same $20 piece, each packaged in a box labelled "Agent 18 Shield for 3G Nano," Agent 18's new EcoShield, NanoShield, and FlowerVest are cases for the third-generation iPod. EcoShield and NanoShield are black with clear and all-clear hard plastic cases, respectively, both with the same two-piece snap-together design. The EcoShield we received for review arrived alone, while the NanoShield's package included a…
