I made a wallhanging for my DH's 50th that was just blocks joined by sashings. One block with the Berlin bear; a German flag; a ship (coming to Canada); a couple preprinted eagle squares; an appliquéd bike; appliquéd weights (barbells); and a Canadian flag; with the center block embroidered with Families are Forever & some wedding rings. Maybe something along that line for your DH's interests would be an idea, rather than an intricate pattern?
Here's an idea for one of his blocks.
http://www.purlbee.com/mini-quilt-vegetable-patch/