The Guggenheim’s Findings Blog turned up a interesting image & story on Michael C. McMillen:

FINDING 53: ILLUSTRATED LETTER FROM MICHAEL MCMILLEN TO DIANE WALDMAN, 1983
In preparation for New Perspectives in American Art: 1983 Exxon National Exhibition, curator Diane Waldman traveled throughout the country to view recent works of contemporary art and meet with artists. This letter from California-based artist Michael McMillen to Waldman mentions meeting her during her recent trip to Los Angeles and informs her of his upcoming trip to New York. He expresses his excitement about seeing the Solomon R. Guggenheim Museum in person and instead of mentioning the museum by name, he includes a small illustration of the museum’s iconic Frank Lloyd Wright building.
The Exxon-sponsored exhibitions of contemporary art ran from 1978 to 1987 and alternated each year between national and international exhibitions. McMillen had ten works on view at the 1983 exhibition, including an installation entitled The Witch of Draconis. Installation plans and proposals for this work can also be found in the Guggenheim’s archives. –Amanda Brown, Archives Assistant
Michael is currently installing Station 9, a new work in the viewing room at L.A. Louver. Opening 22 March 2012!