After boarding our cruise ship in Yokohama we sailed to Hiroshima. Besides Itsukushima Jima, we went to a large Edion store/mall that had numerous used and new electronics, games and anime stuff. But as much as they had, it doesn't seem like Japan has any Star Trek memorabilia.
I personally loved Itsukushima island, and its many historic buildings and shrines. It has a couple of very nice and long mountain trails. One we had to turn around at about 1/2 way as we didn't have enough time or energy to complete it.