Kappabashi is an area near Ueno that sells all manner of kitchen/restaurant related goods. A friend of mine found a charming noren (kind of a split curtain often hung up at restaurant entrances when they're open) there that I intend to track down someday.
This site lets you search for shops that sell specific items of interest (Japanese only):
However, no tofu molds came up. Who knew it was so hard to find a mold for making tofu! (A request from a friend). I've only been able to find wooden ones, nothing like this one here. Tokyu Hands no longer carries the stainless steel model pictured in the post