Elevate Structure, a Hawaiian tiny house company, envisions adding compact and affordable housing in cities around the U.S. — without sacrificing parking. The firm’s pre-fab design props the small dwellings on top of a trunk-like base so they float over the asphalt. Add “tree trimmings,” with exterior walls finished in leafy greens to reduce air pollution and a roof that funnels rainwater into the hidden storage tank in the “trunk,” and you’ve got sustainable architecture…