I was watching a program on Japanese television the other night in NYC and there was a segment on various wholesale markets in the Tokyo area. Besides Tuskiji, which everyone knows about, there's one in Yokohama, and one in Ota-ku, near Haneda airport, which I had no idea about.
From what I'm starting to gather from an online search, the Ota wholesale market is even larger in space than Tsukiji and is a consolidation of a few markets (flowers, produce, fish, etc.) that were located in other sections of the city in older buildings. And while most of the businesses are wholesalers, there's a lot of shopping available for individuals. And of course, there seems to be some good eating to be had as well.
I wish I had known about this, since I usually stay with my relatives in Ota-ku, and it seems like it's pretty nearby. I guess this will be another itinerary item for my next Tokyo visit.