I like this idea, but I'd prefer that there be a few different widths of wood fencing. "brilliant and cheap idea of purchasing sections of cedar picket fencing from [shudder] Home Depot, cutting off the tips, and turning them on their sides.
Magnolia 'Little Gem'-easily controlled to te height range that suits your requirements ben. Will generally form a clipped block of foliage over time though not as dense as the lilly pilly we chatted about. *Could be used as a "pleached" hedge(st