In the August-September 1973 issue of Sports Scoop, editor Steve Mitchell (a Net54 member) wrote a three-page article, illustrated with many photographs, about his experiences at the fourth annual Midwest Sports Collectors Convention (the Detroit show) on July 20-22, 1973. Over 1000 people attended, quite an increase from fewer than 100 who attended the first Detroit show just three years before. The highlight of the convention was the auctioning off of a T206 Wagner on behalf of Mike Aronstein (who was not present and did not actually own the card). It was won by Fred McKie (also a Net54 member) for $1100. Last year, in response to a request by TCMA (Andrew Aronstein), moeson posted SPORT FAN's report on the same convention and auction (in this thread:
http://www.net54baseball.com/showthread.php?t=203472), but the scans of the pages seem to be down now.
I also have an even longer, illustrated account of the 1977 Detroit show (attended by 5000 people) from Sports Collectors News, and I'll try to post that too if I can get the pages scanned.