Unfortunately, to be effective beyond any but the closest distances and still work in crowded, noisy conditions, this technology needs to have multiple microphones spread far enough left and right and up and down, so earrings are not a very good candidate (except, as I implied, in close or quieter conditions). A necklace could work. For the same reasons, it would not function as well as a t-shirt or camisole. For me as an engineer, the biggest challenge would be designing the fashion aspect so that it would attractive enough for someone besides a geek to be willing to wear. 😉