Landscape design doesn't always have to be complicated and overdone. Here's a simple tree design which is manageable and yet still adds a sense of personality to the yard - Doyle Herman Design Associates Landscape Design
APLD 2010 International Landscape Design Merit Award Winner Richard G Shuster, RG Shuster & Company, Southampton, NY [Like tall narrow trees planted in a narrow ribbon of stones -- something similar for a b.
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