I'm currently living in Mexico City until the end of the year and want to tour Mercado de Merced with an expert (english speaking) tour guide. I found the posts from 4 years ago but was hoping someone could offer me more current information. I emailed Mexico Soul and Essence but never heard back and they were the only lead I had. I'm living in the Santa Fe area and patronize my small local street market on Saturdays but want to experience the Big Daddy of all markets in el centro. BTW, I'm trying JASO tonight after reading the outstanding reviews on chowhound. Thanks!