"Sunset's New Western Garden Book" has this to say about a variety named Stribling Little Princess: Dense, tight clumps 3 to 4 feet tall; very slow growing, slow to spread.
Beyond that, you might ask your neighbors about where they bought their plants and what they are called.
Nandina height and, to some extent, its breadth can be controlled by cutting the tallest canes to the ground. This will force new growth and keep the bottom filled in.
