Billboard Baron Karl Eller Is Trying To Budge The City Council. By Dave Devine KARL ELLER, A 1946 graduate of Tucson High School, has made millions in several businesses during his professional career. He s so successful the University of Arizona recently named its Business School after him but that might have more to do with the $10 million donation he gave the UA than with the fact that he built a convenience store empire. When he purchased most of Tucson s billboards last year, Eller apparently thought he had enough clout to end the often bitter legalistic battles between the City of Tucson and local