Rolling Stone have a special feature on Cameron Crowe, who once worked for them as a teen reporter (as dramatized in his recent film, Almost Famous). There is a selection (Crowe's Greatest Hits) of his best articles from that period, including one from 1976 about David. Cameron spent several days with David, for most of which period David was wide awake, very active, prolific, and bored! It touches on recording with Iggy, The Man Who Fell To Earth, Liz Taylor, drinking champagne with Ron Wood and Young Americans.
Go here to read the whole thing - its fascinating!