"Spanish" cypress is the traditional wood of choice for flamenco guitars. It’s a formerly cheap and plentifully available Mediterranean wood which is wonderfully aromatic and easy to work. For much of the Spanish guitar’s early life this cypress was the poor man’s wood for backs and sides; it was the most common default material for anyone who could not afford the more expensive rosewood. For all its humble origins, though, and in spite of its comparative lack of density, properly cut and selected Spanish Cypress has at least as good a "Q" as East Indian rosewood and a much better one than maple. Even though it isn’t used for making steel string guitars, I know of no reason at all why it wouldn’t work very well on them.