SandiegoMark, I think you may be thinking about Bill Bramlage's layout. See OGR Run #278 June/ July 2015 page 46. If that is the HO factory you are referring to, there was a story about how he converted it for O gauge use. He added a foundation, modified the door sizes, and added O gauge figures and machinery. I do not have the OGR Run # for the story his conversion but I know there was one.
www.modeltechstudios.com sells some figures of machines and operators.
Let me know if you want more information.
Paul Goodness