Stephen Howell, owner of Howell Design & Build, North Andover, Mass., remembers what it was like when he founded his company six years ago. "I don't know a bonus system that exists that doesn't have the potential to be interpreted as unfair," says David Bryan, owner of Blackdog Builders, Salem, N.H., whose four-year-old bonus system based on gross profit distributes rewards to field crews for productivity. More