When I think of Japanese gardens I think of moss. Why don't you try a simplistic set up with moss, a gravel path, and a few well-placed miniature plants to go with the other decorations?

Try a Google search for Japanese gardens and then think of how you can incorporate the general idea inside your terrarium.

Here is a link that might be useful: Garden lanterns etc.

You could use "lucky bamboo," miniature spicies of mondo grass, and bonsai plants.