Here in Sydney, in the Sutherland Shire, they got a small comemorative japanese garden. It was a gift from the Japanese Government! It is surrounded by walls, it has a wood bridge over gravel, rock and where it is suposed to have moss it has 'dwarf mondo grass' forming a dark green carpet. Rocks and steping stones! It looks great. I have planted some "dwarf mondo grass" near the steping stones leading to the water basin and after a year, it begun to form this "carpet" feeling. I'm also using a native ground cover which brings up another green tone to the design, 'dichondra repens'.
In the begining I only wanted traditional japanese plants, but after reading about a japanese gentlemen who design japanese gardens in Adelaide SA, I opened my mind to experiment with other plants that can put up with the australian summer.
Go for the mondo grass! Where people use the place for walking, place some steping stones and some rocks. Add liriope around some places...
Cheers, Vince. PS. don't be symetrical!