My names are similar enough that people know I'm boxing: Osaar, Isaar, Esaar, Usaar and, um, Harmsworth, but I find keeping the first letters different at least helps me tell myself from myself. I also stop just short of the clone army look and give each toon the same face and coloring, but a different hairstyle. I remember that Isaar has the prim up-do, Osaar has the sporty ponytail, etc. I don't PvP, but I don't think anyone would have trouble figuring out my main if I did ... in PvE, people just watch for the toon in front, leading the others, and send all their "WTF? LOLOLOL" messages to her.