A post by James Iry on the Scala mailing list today reminded me of the existence of FF Scala (along with its companion FF Scala Sans). I haven't received confirmation, but I suspect that Programming in Scala does not, unfortunately, use any members of the FF Scala family. I was sorely tempted to purchase the fonts, until I saw the prices. Maybe someday.
And there are plenty of other Scalas about. In San Francisco: