Bowie busied himself creating a film, set in Hunger City, using primitive video techniques. I remember helping him to construct a miniature Diamond Dogs set in his hotel suite living room, and to film him walking electronically through the set. The script was actually the videotape itself at one point. I've never seen it written down on paper, althought I'm sure it exists in that form by now.
Tony Visconti tells what Bowie was doing in 1975, 'Strange Fascination' (2001 edition)